“And then Valentine had told them they were brother and sister, and Jace had realised that there were worse things, infinitely worse things, than Clary leaving him for someone else -and that was knowing that the way he loved her was somehow cosmically wrong; that what had seemed the most pure and most irreproachable thing in his life had now been defiled beyond redemption. He remembered his father saying that when angels fell, they fell in anguish, because once they had seen the face of God, and now they never would again. And he had thought he knew how they felt.”
―
Cassandra Clare,
City of Fallen Angels