This is my apocryphal theory: The Devil never really betrayed God, he is just pantomiming being his adversary to make God look more benevolent and the only alternative for salvation.

The Devil tempts people to fall into sin so that they end up in hell and being tortured for ever, just as a cop under cover pretends to sell or buy drugs and then arrests those who fall into the trap.

This role is even consonant with his Angel name: Lucifer, the light of God. For there to be light there must be darkness, so Lucifer takes the role of that darkness.

(For the record: no, I didn’t read Ssndman or Predicator, nor saw the Lucifer TV Show, so I don’t know if this theory is already known. If so, please share where I can read more about it, thanks!)