Heidelberg Catechism, commissioned by Elector Frederick III "the Pious" of the Palatinate and written by Caspar Olevianus (Olewig) and Zacharius Ursinus (Baer) in 1563. Its first question and answer make it one of the most beloved of the Reformation-era catechisms:
Q. What is your only comfort in life and in death?
A. That I am not my own, but belong—body and soul, in life and in death—to my faithful Savior, Jesus Christ. He has fully paid for all my sins with his precious blood, and has set me free from the tyranny of the devil. He also watches over me in such a way that not a hair can fall from my head without the will of my Father in heaven; in fact, all things must work together for my salvation. Because I belong to him, Christ, by his Holy Spirit, assures me of eternal life and makes me wholeheartedly willing and ready from now on to live for him.
Yes, it's a little on the long side and perhaps not easily memorized. Therefore, in the interest of enabling believers to commit it to their hearts, I here link to my own musical rendition of the first question and answer: I Belong. The text I wrote back in 1986, and the music I composed in 2001. The text follows below:
In life and death, this is my only comfort:
that I belong, in all I do and say,
not to myself, but to my faithful Saviour —
to Jesus Christ, who took my sins away:
with his own blood he made for me atonement
and freed me from the temptor's evil sway.
The Lord provides, for he is very gracious:
he watches over me, therefore I know
that not a hair can from my head be taken
without my Father's willing it be so;
and I believe that all things work together
for my salvation from infernal woe.
Yes, I belong — and this is my true comfort —
to Jesus Christ, who tells me constantly
that I am his and, through his Holy Spirit,
assures me that I'll live eternally;
he makes me want to serve him now and always,
and live in every way obediently.