Out of the Silent Planet saves its allegorical work for the end when Ransom meets the Archangel of Mars (Malacandra). Even there, one has to have been brought up on the Bible in a living and abiding way (esp. the books of Daniel and Isaiah) to connect Oyarsas to (planetary) archangels, and Malacandra's tale of The Bent One and his fall (wounded in the very light of his light = and I saw Satan fall from heaven like lightning) to Lucifer. Likewise, "Thulcandra" = The Silent Planet, that is earth, a world from which no news comes, because our Oyarsa has become "Bent" and our world is quarantined. And the nice addition of Malacandra telling Ransom that the Maleldil (meaning "Friend of the Eldila" or angels, God the Father) has "taken strange councils" and dared terrible things, and how these are things that the out-of-the-loop Oyarsas "desire to look into". One raised on the Bible will immediately pick up on this. But it's not likely anyone else will.