It starts with him in heaven, an angel with a deep love and reverence for God and her creations, a love that he then pours into his work to bring Her vision of the stars to life. But just as he begun his work, he is given a message from God through Aziraphale that can be effectively summed up to “nothing lasts forever”. The physical manifestations of Crowley’s passion and love will be erased in, what is to an angel, a blink of the eye. For forever God has always been the designer and Crowley, as an angel, has always been there to simply carry out Her plans. But it is here that Crowley begins to question and strain this unspoken relationship, desiring change.
So despite being warned, Crowley dares to test his relationship with God and questions the unspoken, only to be rejected and abandoned by her in the most visceral way imaginable. It was here that Crowley began his fall.
As a demon, Crowley comes to love Aziraphale and, just as he did with God, he expresses this intense love through acts of service. He takes him out to eat, he saves him, he bends at every whim to keep him happy and safe, and yet nothing is ever explicitly said. Instead they dance around each other and communicate in code, and so Crowley is left to assume.
But then just as with God, Crowley pushes his luck and says too much, asks for too much. He questions the comfortable unspoken dance they’ve been doing for centuries and asks for something more. In response, Aziraphale parrots what he had said in the very beginning, except this time it’s his own words: “nothing lasts forever”. Not the stars, not the bookshop, not love.
So despite being warned, Crowley kisses Aziraphale, posing his most desperate question. In return, he is rejected and abandoned by Aziraphale in the most visceral way imaginable.
Aziraphale’s “I forgive you” is a very loaded response, and while it rings as an attempt to call back to his and Crowley’s old unspoken routine, it also reminds me a lot of God. Crowley falls in act of sin, and while God punished Crowley, She also forgives him for being a sinner because God forgives all sin. So Aziraphale forgives Crowley because again he has sinned. Again he has fallen.
At this point we realize Crowley did not just fall, that’s past tense. Rather, Crowley is falling. He continues to love, dares to show it, and thus suffers the consequences.
I think another big thing to consider about the end of ep 6 and Aziraphale’s decision to try and change heaven is what he just saw take place with Gabriel a few minutes beforehand.
His ex-boss Gabriel that, to Aziraphale at least, embodied everything wrong with how heaven thought and operated just had a complete change of heart and rejected heaven. So it’s possible that in Aziraphale’s mind, if one of the highest ranking angels had been able to change and reject the system, then it’s possible for everyone else in heaven to change as well. I think that’s also why he felt Crowley would have such a vital role in that change, because he believes there is so much to love in Crowley and he hoped that he would be able to show that to heaven and make them change too, just like he and Gabriel had changed partly because their love of a demon.
I think the Metatron kind of topped off that hope by making it seem that he was receptive to departing from the status quo as well. He mentioned that he too has tried human food and insists that Aziraphale indulges unlike the other, more uptight angels that belittled him for his interest in human delights. He then waxes off about how Aziraphale would be a great influence on and leader of heaven despite him going against heaven on so many occasions, which Aziraphale might have taken to mean that the Metatron would be receptive to altering the system to be more inline with Aziraphale’s philosophy.
So of course if both the Metatron and Gabriel, the two (or well, formerly in Gabriel case) highest ranking individuals in heaven sans God herself, had been open to change/abandoning the old heaven, then Aziraphale had a solid chance at changing the system to help everyone, especially Crowley and himself.
Just some food for thought