What more can we do before God that is greater than these two services—the services of prayer and thanksgiving? In the first place, one must hear the Word, which is given to us by God. Here we do nothing, but we only take hold of what has been offered. In the second place, one must pray and implore God’s help after the Word has been heard and taken hold of, and after getting this help one must give thanks and offer sacrifice. But we pray not only with the mouth or the voice but also with sobbing of the heart, with all our strength and members. This is prayer without ceasing (cf. Acts 5:12; 1 Thess. 5:17).

-Luther on Genesis 32:18 (AE 5)