“Never think that you are kneeling or standing alone, rather think that the whole of Christendom, all devout Christians, are standing there beside you and you are standing among them in a common, unified petition which God cannot disdain. Do not leave your prayer without having said or thought, ‘Very well, God has heard my prayer; this I know as a certainty and a truth.’ That is what Amen means.”

Luther, Martin. “A Simple Way to Pray” (1535) Luther’s Works Vol. 42. (Philadelphia: Fortress Press, 1969), page 198.