Kierkegaard:

So to pray is to breathe, possibility, is for the self what oxygen is for breathing. But for possibility alone or for necessity alone to supply the conditions for the breathing of prayer is no more possible than it is for a man to breathe oxygen alone or nitrogen alone. For in order to pray there must be a God, there must be a self plus possibility, or a self and possibility in the pregnant sense; for God is that all things are possible, and that all things are possible is God; and only the man whose being has been so shaken that he became spirit by understanding that all things are possible, only he has had dealings with God. The fact that God’s will is the possible makes it possible for me to pray; if God’s will is only the necessary, man is essentially as speechless as the brutes.