Some people will say Superman was inspired by Jesus, others will say it was Moses. Some people will say his creators, Jerry Siegel and Joe Shuster, wouldn't have liked the modern Jesus parallels created by the movies merely because they were jewish, and jews have no love for Jesus, so Superman's inspiration instead had to come from Moses for this reason.
This is a moot point though considering that both Richard Donner (born Richard Schwartzberg) and Tom Mankiewicz are jewish, and they first introduced the Jesus analogy in the 1978 Christopher Reeve Superman movie.
They did so as a way to help get audiences to take the character more seriously in order to contrast with the sheen of camp left on superheroes by the 1960s Adam West Batman TV show, which was the public's last major enduring recollection of superheroes at the time, and would need to be reconciled for an earnest telling of a superhero to be accepted by mainstream audiences.
The "Superman/Jesus analogy" -- something serious like religion, paired with something that may have not been taken serious by anyone, like comic books/cartoons -- helped to achieve the necessary gravitas, and, while such an allegory may be unnecessary today in an era where superheroes are taken seriously on their own and dominate the mainstream, it was a wise decision for its time.
Bryan Singer and David Goyer, also jews, continued and amplified the Jesus parallels in Superman Returns and Man Of Steel.
But other than a few heroic qualities, comparisons between Superman, Moses (and Samson for that matter), and Jesus don't really make sense, as Superman is quite their opposite in many defining aspects. Not only are they more different than alike, it is really even a stretch to say that they are similar. Consider:
Jesus was sent from safety in heaven to danger on earth, while Superman was sent from danger on Krypton to safety on earth. Jesus was sent with a special mission to save the world, but Superman was sent away to save himself, and his only mission was to stay alive.
It is true that Moses was sent from danger to safety, but he was also taken care of by his biological mother once he was safe. Superman had no biological parent around to nurse and/or influence him. (And as for Samson, he only had strength in temporary instances when the Spirit Of The Lord came upon him, and not all the time)
Jesus is the son of God, and Moses was called of God, so both became heroes because of God and not because of their environments, whereas Superman is the opposite.
Superman is only a hero because of his environment, the place in which he grew up, not because of who his biological parents were, or a "divine mission" he was sent on. In fact, Superman being sent away for any reason other than (or in addition to) his own safety makes no sense in the context of his story, and actually detracts from the urgency of the emergency in his origin.
Imagine that your house is on fire, and you can't get anyone else out but your baby at the last minute, and you manage to place your baby safely on the lawn, out of the flames. Does it make sense that you place this baby out there with the partial purpose of it growing up and becoming a police officer two counties down?
In fact, it would sound like the situation isn't that urgent if you had time to plan all that. Kal El was sent to earth in an emergency, makeshift spaceship, because Jor El didn't have enough time to make a ship large enough to transport the entire family (or planet population), much less a super cousin to babysit his son, or a super dog, super clothes, kryptonian memorabilia, a special predestined fate for his son to live out, etc.
So Superman is good not because he is the son of Jor El, nor because he is called of Jor El, but because he is Clark Kent, and was raised by the Kents, who happened to be really good people, and discovered him by chance.
Joseph and Mary had no influence on whether Christ was the son of God, just as the Pharaohs had no influence on Moses being called of God, but without the Kents, there is no Clark Kent, and without Clark Kent, there is no Superman. Jesus still would have been the Son Of God whether Mary and Joseph raised him or not, and Moses still would have been called of God whether he grew up with the Pharaohs or not, but Clark (or Kal El) never would have become Superman if not for the Kents.
David Carradine got it wrong in Kill Bill: while Superman always has powers no matter what (unless one of his rare weaknesses are present of course), it is Clark Kent who is the real person, and it is he who created both the Superman costumed identity and the Superman clothes, the "S" shield/symbol, and the name, as well as the mild mannered reporter Clark Kent disguise. One is a costume, the other a facade, but both are created by Clark Kent.
The reality is that Superman was not inspired by Jesus or Moses (or Samson), and no religious symbolism served as the inspirational basis for Superman at all, biblical or otherwise (including myths).
So what is Superman inspired by exactly?
Is it being an immigrant, a fish out of water, "alien", because Superman's creators were the children of immigrants?
No, it's not that either, because being an alien was just the excuse for the superpowers in Superman's original stories and not the driving force of his character as a "fish out of water" narrative, for he knew the earth well having grown up there, it was the only home he knew. Being an alien was just the in-story explanation that Siegel & Shuster used as a springboard to tell the stories that they really wanted to tell, which were stories about a man who was tremendously strong, fast, who could hardly be hurt, and did heroic deeds.
There is a reason why Krypton only gets one panel in the original published Superman origin in Action Comics #1, while the rest of the story is spent on earth with Clark Kent, and that is because Krypton is only the explanation for Superman's superpowers, nothing more.
Siegel & Shuster's Superman knew nothing of Krypton or the fact that he was an alien until many years into his career as Superman, after he was already an adult and had created his heroic crime fighting identity and mild mannered reporter persona, and no one else Superman interacted with knew he was an alien, either.
The "stranger in a foreign land", "fish out of water", snobbish Superman who missed and pined for "his life on Krypton" (that he wouldn't have remembered considering he was a baby anyway), who counted Krypton as his true home over earth, did not take off until the Silver Age, and was an example of too many years of familiarity and external knowledge of Superman's history manifesting itself internally from the story perspective (i.e, "we as fans know that Krypton is an important part of Superman's origin, therefore, it must be the most important thing to him in his stories").
This could not be more wrong.
What Superman really has his origin in, moreso than anything else, is the eugenics craze of the turn of the 20th century.
It was the hot new science that was everywhere, in everything, and Superman's creators, Jerry Siegel & Joe Shuster, had absorbed it through osmosis, if not deliberately, as it is no secret that the two were avid science fiction fans, and science fiction is inspired by popular science.
Here is a brief history of eugenics in the United States at the turn of the century:
In 1904, the Cold Springs Harbor Research Facility was started in the United States by eugenecist Charles Davenport.
In 1907, the first sterilization laws were passed in the United States. Citizens with mild deformities or low test scores on their report cards were taken and sterilized.
In 1910, the US Eugenics Record office was set up, by then, the British had created the first network of social workers expressly to serve as spies and enforcers of the eugenics creed that was rapidly taking control of western society.
Social workers would decide who would have their children taken away, who would be sterilized, and in some cases, who would be quietly put to death (murdered).
In 1911, the Rockefeller Family exported eugenics to Germany by bankrolling the Kaiser Willhelm Institute.
At the 1912 International Eugenics Conference in London, eugenics becomes an international craze, and gains superstar status. The futurist and best selling sci fi author HG Wells had studied biology under top eugenecists and was spreading the new vision worldwide.
In 1916, HG Wells fan Margaret Sanger starts her promotion of eugenics in the United States.
In 1923, Sanger recieves funding from the Rockefeller family.
By 1927, eugenics hit the mainstream. The "science" was aggressively pushed through contests at schools, churches, and at state fairs.
Churches competed in contests with big cash prizes to see who could best implement eugenics into their sermons, with a few major denominations even claiming that Jesus is for eugenics.
That same year in the United States (1927), more than 25 states passed forced legal sterilization laws, and the Supreme Court Ruled in favor of brutal sterilization policies.
The 1934 film Tomorrow's Children brought the eugenics agenda to the movie screen as a cautionary tale.
Around this time a little earlier, in 1933, Jerry Siegel & Joe Shuster published "The Reign Of The Superman", also a cautionary sci fi tale about a scientist who gained superpowers through eugenics.
A few months later, Siegel & Shuster changed the idea into a Detective character who didn't necessarily have superpowers, but possessed the abilities of an olympic athlete, though Siegel & Shuster said he was "Popeye, but if he were a detective". The story was rejected, and Siegel believed it was because of Shuster's art. Shuster burned all the pages of the story, and only its cover remains today.
A short time later, Siegel and Shuster redid the idea, this time as the character that audiences all over would eventually come to know and love, but Siegel went to Buck Rogers artist Russell Keaton in 1934 to illustrate the short story instead of Joe Shuster this time.
This version of Superman would be a costumed adventurer who wore athletic tights and a cape, had super strength, speed, and durability, and could leap super high (an ability admittedly lifted directly from Edgar Rice Burroughs' John Carter of Mars stories).
The source of Superman's great abilities?
He was a highly evolved superman from earth's future, from the last days of the planet earth before it was destroyed in an explosion, sent back in time as an infant to the year 1913, and raised by the Kents (those familiar with Superman: Red Son will remember the ending in which it is revealed that earth becomes Krypton, well, Mark Millar lifted the idea from this, Superman's earliest days).
This is one of the places where the term "Man Of Tomorrow" has its roots, and where it had some literal meaning.
(And here is Mark Millar's reveal that a futuristic earth actually became Krypton at the end of Red Son:
The 1934 future earth Superman story, or one similar to it, would be pitched to multiple publishers and rejected by all of them for the next three years, until finally it sat in the office drawers of what would eventually become DC Comics for about a year or so, and a publisher was scrambling for stories to fill their new comic book title, "Action Comics". He reached into the drawer and grabbed the Superman story, and liked what he saw.
And so Jerry Siegel & Joe Shuster were hired to do full Superman stories for Action Comics number 1 in 1938, but with an exception: the futuristic time travel element of the Superman story had to go.
For whatever reason, the publishers felt the idea of a highly evolved Superman from the future sent back in time as a baby to save himself from the exploding earth on its last days, who was found and raised by a kindly couple, and became a costumed hero as an adult, was just too fantastic, so Superman was changed to a highly evolved man from the distant planet Krypton, sent to earth as a baby to escape the planet's explosion in its final days, raised by a kindly couple, who became a costumed hero as an adult, and the rest is history.
Superman was the clear product of the zeitgeist at the time. If Superman hadn't been created by Siegel & Shuster, in many ways, he would have been invented by someone else (and Captain America is even more eugenics inspired than Superman is).
The secret identity of Clark as the mild mannered reporter was born from wish fullflment, power fantasies, lifted from Harold Lloyd films, who played meek and mild when he wore glasses, and would whip them off to become a fighting fury when bullied. (Clark Kent, that is, the real Clark, would pretend to be mild mannered in his disguise as a reporter, and would use this identity as a vehicle to find out where he would be most needed as his costumed Superman identity)
But something happened to Superman: once he became famous and well loved the world over, everyone started to take credit for him.
Suddenly, everybody everywhere claimed an influence on Superman, including many of the people who initially rejected the concept, and even people who removed Siegel & Shuster from the strip, as well as people who later forced their idea of what the character should be on the stories in place of Siegel & Shuster (Mort Weisinger comes to mind).
He was used for propaganda -- if ethnic bigotry was condoned by Uncle Sam in propaganda, then Superman was for it, if it was condemned by Uncle Sam in the 50s, then Superman's values shifted to be against it.
Citing any propaganda as a basis for who the character is is shakey ground, as multiple contradictory messages have been pushed over the years, and you cannot have it both ways, for if Superman thinks certain kind of racial talk is "anti american" and bad, then he thinks 'slapping japs" is american and good too, since both messages have used him in propaganda before.
There were christians who were claiming Superman was inspired by Jesus, and the character was used as illustrations in sermons.
Jews were claiming Superman was inspired by Moses and their status as immigrants, and that Siegel & Shuster's jewishness is what created Superman, when it couldn't have had less to do with it (see almost any comic book documentary of the last 20 or so years, and you will see this and similar claims made by pop culture pundits repeatedly, whereas Siegel & Shuster repeatedly say "It just came to them", or offer science fiction and movie explanations for Superman's inspiration).
Superman's parents (The Kents) couldn't even vaccinate him, much less have him circumcised (It is a good chance that the Kents, being farmers in the red state of Kansas in the midwest Bible belt part of the United States, likely belonged to a sect of christianity that does not circumcise, and could probably get young Clark by on a religious exemption for vaccinations as not to reveal his super durability as well).
Liberals claimed Superman was an illegal immigrant. (Which is not really true, as according to United States law, any child found under the age of 5 with no discernable place of origin to which he can be returned to is considered an american citizen. Is Superman a "naturally born citizen"? Perhaps not technically, but nobody in Superman's stories would be able to know or prove that -- no one living, anyway).
And some neoconservatives claimed he was american propaganda, a flag waiver, eager to fight whoever Uncle Sam said to, when the reality is that the american way that Superman fought for was one of truth and justice against the corrupt, which would rule out warmongering.
As for "the american way", Superman always stood for it rather implicitly, in that "Truth and Justice" ARE the american way (idealistically), and why the pilgrims came over to begin with, in that they came over for truth as they saw it in regard to religion, and to escape the injustices put upon them by England.
(As for american citizenship, Clark Kent would have it, but his costumed creation, "Superman", would not, just as Dwayne Johnson is an american citizen, but "The Rock" is his stage name, and the stage name has no citizenship, no credit card, no address, etc, because a stage name/performing/costumed identity has no use for such things. However, in some comics, even "Superman" has been given citizenship in multiple nations)
Superman's creators, Jerry Siegel and Joe Shuster, at around the 38 second mark in this video, say that Superman stands for "exactly the motto in the '50s TV show: 'Truth, Justice, and The American Way'".
https://youtu.be/Y5oH20iHujo
...this, however, was not the same as making him a warmongerer.
Anyway, back to the point of all that, the super mania had hit, and suddenly, everyone everywhere wanted a piece of Superman (or at least his capital).
...And many people got it, which has resulted in the character losing his original appeal, losing touch with the world around him, and being disconnected with audiences today.
Nobody can relate to a holy space ghost messiah sent here to save the world. Over emphasizing the alien aspect of the character puts him further out of the reach of the audience, and makes him boring and personality-less. Making him a fish out of water, stranger in a foreign land denies him human relatability, and the grit and down to earthness that his original stories had.
But a farmer, a man, with the powers of strength, speed, and durability, who sees earth as his home, and faces the same situations that you do, but solves them, that is wish fulfilment, that is relatability with self projection, and that is what made Superman succesful and popular in the first place.
It would be wise for both the comics and the films to rediscover Superman's roots in this regard.
The importance is on the man. Not the "alien".
It's SuperMAN, not Superalien.
John Byrne got this right in his 1986 reboot, where he took the character back to his roots.
All Byrne did was breath new life into the character, except that life was really the old life, the same DNA that Siegel & Shuster imbued theirs with in the 1930s.
Being an alien in Byrne's run was again just the excuse for the superpowers, emphasized by Krypton's other worldy appearance, and the kryptonians speaking a truly foreign language, just as the language spoken by the futuristic earth was an unknown one in the original 1934 Superman short story, a language that even Superman still did not understand in adulthood.
Even aspects of Superman that are considered to be of "alien" origin because of the movies are actually created by him on earth, like The Fortress Of Solitude:
With this in mind, we have yet to see Superman truly done right on the big screen.
I understand that religious allegories may have been necessary for depth at a certain time, but nowadays, Superman can fly on his own, the character is ubiquitous enough to get by on his own merits, and needs only be given the chance to.
So how about it, fandom and hollywood: will you let Superman fly?
It's fine to use Superman (or any character) for the purpose of analogies in your day to day life, including religious, political, or other kinds of analogies, the versatility of the character lends itself to such things, but just because the character can be wrangled to support such allegories and metaphors, does not mean that they influenced the character's creation, or that he was derived from them. It is erroneous to make such claims, and when they are incorprated into history books -- or even worse, the character's internal stories -- they do everyone a disservice, especially the character.
Let's let Superman be Superman.