In "A Simple Way to Pray" (1535), Martin Luther writes:

If I have had time and opportunity to go through the Lord's Prayer, I do the same with the Ten Commandments.

I divide each commandment into four parts, thereby fashioning a garland of four strands. That is, I think of each commandment as, first, instruction, which is really what it is intended to be, and consider what the Lord God demands of me so earnestly. Second, I turn it into a thanksgiving; third, a confession; and fourth, a prayer.

[Luther demonstrates his approach for the first commandment, "I am the Lord your God. ... You shall have no other gods before me."] Here I earnestly consider that God expects and teaches me to trust him sincerely in all things and that it is his most earnest purpose to be my God. I must think of him in this way at the risk of losing eternal salvation. My heart must not build upon anything else or trust in any other thing, be it wealth, prestige, wisdom, might, piety, or anything else.

Second, I give thanks for his infinite compassion by which he has come to me in such a fatherly way and, unasked, unbidden, and unmerited, has offered to be my God, to care for me, and to be my comfort, guardian, help, and strength in every time of need. We poor mortals have sought so many gods and would have to seek them still if he did not enable us to hear him openly tell us in our own language that he intends to be our God. How could we ever-in all eternity-thank him enough!

Third, I confess and acknowledge my great sin and ingratitude for having so shamefully despised such sublime teachings and such a precious gift throughout my whole life, and for having fearfully provoked his wrath by countless acts of idolatry. I repent of these and ask for his grace. Fourth, I pray and say, "O my God and Lord, help me by thy grace to learn and understand thy commandments more fully every day and to live by them in sincere confidence. Preserve my heart so that I shall never again become forgetful and ungrateful, that I may never seek after other gods or other consolation on earth or in any creature, but cling truly and solely to thee, my only God. Amen, dear Lord and Father. Amen."

These are the Ten Commandments in their fourfold aspect, namely, as a school text, song book, penitential book, and prayer book. They are intended to help the heart come to itself and grow zealous in prayer.