I believe it's important to establish what a star is. It's a giant, flaming ball of plasma undergoing nuclear fusion [NASA, "Star Basics"], but if a sufficiently large round mass with its own "cleared orbit" becomes subject to a star's gravitational pull (and makes the star subject to its own, albeit less) that star becomes a "sun," having attracted a planet [Wikipedia, "Clearing the Neighbourhood"; Wikipedia, "Planet"; NASA, "Gravity & Mechanics"]. If there are no other masses around the star, then it is simply a star. From the perspective of us humans, a sun is generally preferable to a regular star, as a sun's solar system contains within it the possibility for life. In fact, the sun is associated with power over life (and death) for myriad reasons, many relating to crops, health, and safety.

Religious Influences

The Kryptonians worship the Sun God Rao, sometimes believed to be inspired by the Egyptian God "Ra." Rao is the name of both the omnipotent deity who governs the sun and the sun sphere itself. Rao became the singular Kryptonian deity of note following a great flood predicated by the prophet Jaf-El, the brother of Kal-El's distant ancestor Tio-El [Krypton Chronicles (1981) #3]. Prior to the flood, Jaf-El demanded his fellow Kryptonians abandon polytheism in favor of monotheism, i.e., the worship of Rao, and was promptly rejected until an optical illusion convinced his audience of Rao's presence and wrath. Many mythologies do in fact carry some myth or other of a flood; however, given that the cited story explicitly references Noah's story from the Book of Genesis, inspiration for the story is easily attributed to the Hebrew Bible. This is further legitimated by the text. Just as God punished mankind for its wickedness, so did Rao, by sending a flood to decimate all Kryptonians. Other than the arks, which were eschewed in favor of winged animals, the base story is fairly similar.

Another event seemingly inspired by the Hebrew Bible — the one of David and Goliath in the Book of Samuel, exactly — was the Kryptonians' rebellion against their tyrant enslaver Taka-Ne [Superman (1939) #264]. This one involved the Kryptonians using headbands to launch rocks at their enslavers until the enslavers fled, from which the Kryptonian headband commonly seen on characters such as Jor-El was derived. From then on, this headband, which Supergirl would eventually claim as part of her costume, would denote clan belonging then citizenship on Krypton. Later, a boy aptly named Val-Lor would inspire a rebellion against another set of enslavers called the Vrangs; not only was this act of bravery lauded in Kryptonian history, signifying the value of rebellion, but the Vrangs would eventually return to menace Superman, forcing the Phantom Zoners to assist him with defeating them out of centuries-old spite [Superman (1939) #176; Action Comics (1938) #548-549].

Superman's origin is also a Moses allegory, with his journey in the rocket to Smallville evoking imagery of Moses being hidden in the Nile. Author Len Wein also referenced the Hebrew Bible in [Superman #338], entitled "Let My People Grow!," in which Kal-El and his cousin Kara Zor-El freed the Kandorians from approximately 30 years of captivity under Brainiac. Kal and Kara flew them to a planet much like Krypton which the Kandorians called "Rokyn" or "Rao's Gift," much like Moses leading his people to the promised land during the Exodus.

Putting the history aside, many Kryptonian rituals of significance — e.g., weddings and naming ceremonies — occur under the concentrated light of a red sun [Action Comics (1938) #378, #484], and everything from nursery rhymes to prayers to swears involve the sun god Rao in some capacity [e.g., Action Comics (1938) #299, World's Finest (1941) #297]. Additionally, the prevalence of the ending "-ra" in Kryptonian women's names ("Lara," "Kara," "Allura," "Thera," "Faora," etc.) [Krypton Chronicles (1981) #3] does suggest possible references to Rao are popular naming conventions, as the possessive form of "Rao" is "Ro" (masculine) and may be "Ra" (feminine) [Krypton Chronicles (1981) #2]. All this to say, Rao is implicitly and explicitly an important figure in modern Kryptonian culture, in the same way that Abrahamic religions worship some version of capital-G God and incorporate that into things that are not necessarily religious in themselves.

Kal-El was officially named (christened) under the light of a red sun [again, see Action Comics (1938) #378]. When Krypton was on the verge of exploding, and his parents were readying to send him away, Lara told Jor-El that she would stay with him because "Kal-El was born to live among the stars." [Superman (1938) #257]. This statement is intriguing because it reveals a belief that one's name controls one's destiny, otherwise known as nominative determinism.* If we assume that this is a belief persistent on Krypton, despite their otherwise science-based actions and philosophies, then it stands to reason that Kal was named Kal-El as a signal toward some higher calling. Mind, both Lara and Jor-El were "star-inclined" in their own right; Lara was an astronaut, while Jor-El was more of a Jack-of-all-trades including rocketry [e.g., World of Krypton (1979) #1]. Jor-El also wore a red and yellow sun symbol on his green shirt, which distinguished him from his twin Nim (who wore blue, purple, and white [World of Krypton #1; Adventure Comics #304]) but not from his father Jor-El I [again, World of Krypton #1]. Both Jor-Els (as well as Jor-El I's brother, Zim, accidentally) made advances in rocketry which ultimately led to Kal-El's successful landing on Earth.

*It's worth noting that a letter to the editor in Superman #226 made a joke about a hypothetical son of Superman born on Christmas named No-El was rejected by the editor for Superman because naming someone "No" would give them bad luck. Additionally, Kru-El (the Phantom Zone villain) is Jor-El's cousin, signaling that the nominative determinism route may have some (support.

If the act of holding one's child under the red sun was meant to act as a blessing on Krypton, and if we assume for argument's sake that nominative determinism was a prevalent belief on Krypton, then the act of naming one's child Kal-El while having a background in star-related fields and being on a planet that one knows to be dying constitutes a blatant attempt at saving their life. While Jor-El and Lara would use scientific means to save him (mind, that were not as well tested as they could have been, given prior history of failure and the banning of rocket experiments as a result [e.g., World of Krypton]), Jor-El also says "May the winds of space favor his course," [Superman #257]. Space wind is also known as solar or stellar wind, which is a stream of charged particles released by stars [Wikipedia, "Solar Wind"]. In other words, it's still something of a plea, if very indirect, for the god and the star named Rao — and suns and stars thereafter — to help their son. Superman is referred to as "star-child," "star-born," "a titan of the stars," or something similar is continued across the pre-crisis universe, both in dialogue and in the narration text, signaling its relative importance to his lore.

The fact that Superman gains his powers from the yellow sun is a well-known fact, even amongst those who are not otherwise fans of DC. However, many people do not know or have forgotten that he is powered by all yellow stars and that they need not even be yellow for him to derive some sort of power, so long as they are not red (or green, though that is rarely mentioned). A red sun is a sun that has dimmed significantly due to its age. The exception for red is explained by the fact that on his home planet — which had a red sun and greater gravity — Superman would not have any powers; thus, any situation which mimicked one or both conditions would depower him [e.g., Superman (1939) #191, 206]. However, given the religious and cultural importance of the red sun and its linkage to the god Rao, it is not difficult to extrapolate that Superman's vulnerability under a red sun may very well be symbolic of being subdued by or an agent for a higher power. A superpowered being who can move and even relight suns [e.g., Superman (1939) #415] being rendered powerless by one that is red, for the sheer fact that it doesn't *provide* him enough power, is forced to once again succumb to the whims and circumstances of his environment. In some circumstances, if Superman does not account for his escape, he will be trapped in whatever land exists under that red sun [e.g. Action Comics (1938) #300]. This rolls over well into Kal's relationship with higher beings and entities; he interacts or is associated with one at least a few times over the course of the pre-crisis universe. He encountered an entity implied to be capital-G God (Rao) directly in [Superman Annual #10: The Sword of Superman; DC Comics Presents (1978) #29], was called "the Master Programmer's Angel of Death" by the new and improved Brainiac that viewed all of Creation, in [Action Comics (1938) #545], prayed for Rao to fix a rift in the dimensions (which worked) in [Superman Spectacular (1982) #1], and was visited by Kryptonian spirits in [DC Comics Presents #82].

Given all of the aforementioned, it's not far-fetched to suggest that Kal-El (at least in pre-crisis) is quite literally meant to be a "Voice of God." He derives his powers from the stars — also known as heavenly bodies — and is only vulnerable to two colors out of the entire spectrum (again, red and its direct opposite, green). The stars can revive him and, in the vast majority of circumstances, heal him from diseases and injuries that would otherwise be fatal.

It should also be said that pre-crisis Kal-El, under the influence of a red sun, tends to respond "humanly" and grows wild and unclean after too much time away from either the light of a yellow star (or otherwise non-red and non-green stars) or civilization. To be himself, he must have the light of a yellow star. This means undergoing whatever trials and tribulations exist for him under that red star in order to escape its light, much like the character tests of various myths.

Potentially Religious/Indirectly Religious Influences

In situations where Kryptonite is present, there's largely nothing religious to compare it to, of which I'm aware, but exposure to the yellow sun does not relieve or lessen the impacts of Kryptonite radiation. Only removal of the Kryptonite does. We could conceptualize that as (symbolic of) another test of character and strength, but it is also true that Superman's fear is derivative of the nuclear fear of the Cold War. In that sense, we could understand it as something that is ultimately meant to bond Kal-El and the people (usually Earth humans) whom he protects, even though villains use it to do him harm. Next to a red sun, magic, and things of Kryptonian origin, Kryptonite is one of the few things that can weaken or kill Superman, making it apt as a symbol of fear.

With regard to magic, Kal-El is also vulnerable to the magical, mystical, and preternatural, which is understood by some to be devilry (though I'm not entirely sure if that has strict roots in religious texts). If we assume for the sake of argument that to perform magic is to generally disorder and warp that which should be beyond one's control and that supernatural creatures are generally considered abominations, then magic's positionality as the counter to a science-based world, a world in which we can presume Rao exists (on some level) also explains why it can affect Superman. Not only is it not scientifically justifiable, which Superman's existence is in DC lore, but it also somewhat contradicts intelligent design, in the sense that an intelligent designer would leave some things but not others in the control of the designed. This would explain why Superman was vulnerable to malicious magic, such as that performed by a man who looked conveniently like Satan, Dracula (repelled by holy things), and being turned to stone [e.g. Action Comics (1938) #378, Superman #344; World's Finest Comics (1941) #257]. Interestingly, there was a powerful spirit in [World's Finest Comics #285-288] who wanted to possess Superman but could not, suggesting that to do something truly evil or harbor an evil entity, Superman has to be either willing or very susceptible to manipulation. However, Superman can also occasionally turn magic into his advantage but only at the cost of his powers or the need to force magic to mimic/induce his powers [e.g. DC Comics Presents (1978) #18].

The last topic is what it means to live amongst the stars. As aforementioned, Lara said that while preparing to send Kal-El away, in reference to his name. This is where his immigrant and alien identity become relevant again. There was a storyline in which Kara and Kandorian therapists — believing Kal to be depressed and compensating for the loss of Krypton with Earth — tell him that he is actually from Earth. Kal begins to believe it, which causes them to fear that him no longer feeling outcasted means that he will no longer care for others outside of Earth [Superman (1938) #307-309]. Though that's something of a problematic implication, the general sentiment behind it — that Superman should be concerned about the welfare of others, at least partly due to camaraderie, and be willing to leave Earth or wherever he is regularly — does motion toward a type of "live amongst the stars" belief. Kal-El's greatest struggles are relational and psychological, and the fear that he would let these struggles ground him to Earth stems from a fear of him rejecting his destiny. He IS Superman, he was meant to be Superman, he was chosen to be Superman. To be the "Star-Child" is to also allow the stars to nurture and guide you; to be a Titan of the Stars is to preside over them and those who orbit them. Even when Rokyn was established, the Kandorians did not allow him to stay out of duty. They recognized that he had a higher calling than merely dwelling on Rokyn, as much as he wanted to [again, Superman (1939) #338]. That's not to say that Superman doesn't belong anywhere but that he belongs in a fundamentally different capacity. Even the Spectre said as much [again, DC Comics Presents #29], but he said that Superman had not yet developed the mindset for his duty. That suggests to me that Earth-1 Kal, who already loves space, who already is known across many worlds as a savior, has a fundamental psychological paradigm shift to make for himself.

Conclusion

Kal-El's various tensions, based on all of the aforementioned, are not just due to the fact that he is an alien and immigrant, although those take the most immediate precedent on Earth. They originate from the inevitable conflict between someone's power is very close to a deity's and those who simply cannot comprehend such a state and would never be in it. That is also why, in real life, people who complain that making Kal too godlike or too Jesus-y are simultaneously close but not quite there (again, at least for pre-crisis). Kal is a Moses allegory, at the barest minimum, and he also is very much like a deity. Actually, he is arguably much stronger than many, if not most, actual gods in various religious and spiritual myths. The problem is that people largely associate the concept of God or gods with very powerful tyrants or distant creators, and not someone like Superman who is benevolent and good but occasionally makes a mistake or acts in a human manner. In this sense, Kal is more like a demigod. Furthermore, much of Kal-El's modern imagery quite literally makes him "down to Earth" in a way that people tend to appreciate (for many reasons), and they don't want that image dispelled in favor of someone they would fear. Like the fictional DC denizens, they prefer he blend in and not stand out, with the exception of using his powers for the good of humanity. To be Kal-El, the Star-Child, the Voice of God, is to accept a permanent place of ill-fitting or assimilation as (part of) your destiny — at least until you have the mind to ascend to higher things than larping as a reporter who gets shit-talked everyday.