Angels and devils are not enemies, nor are they resentful couples. They are twins, and they have a relationship of forced dependence. It is the evil thoughts of the devil that make the angels holy. Angels also make mistakes, and angels make mistakes for better salvation! The devil also has tears of compassion. And compassion is a nobler emotion, it achieves great love in the world!
"Angel Diary" The close contact between angels and devils, see how angels are made.