The 23rd psalm is a psalm of thanks in which a Christian heart praises and thanks God for teaching him and keeping him on the right way, comforting and protecting him in every danger through His Holy Word. The psalmist compares himself to a sheep that a faithful shepherd leads into fresh grass and cool water. In addition, he shows the table, the cup, and oil also as images from the Old Testament worship and calls it all God’s Word, as it is also called rod and staff, grass, water, and the way of righteousness. This psalm belongs in the Third Commandment (of the Ten Commandments) and in the Second Petition (of the Lord’s Prayer).
Psalm 23 (ESV)
The Lord is my shepherd; I shall not want.
He makes me lie down in green pastures.
He leads me beside still waters.
He restores my soul.
He leads me in paths of righteousness for his name's sake.
Even though I walk through the valley of the shadow of death,
I will fear no evil, for you are with me; your rod and your staff, they comfort me.
You prepare a table before me in the presence of my enemies; you anoint my head with oil; my cup overflows.
Surely goodness and mercy shall follow me all the days of my life, and I shall dwell in the house of the Lord forever.
Lord Jesus, who alone is that one Good Shepherd, thanks be unto You for all Your spiritual and bodily benefits. Let the Word of Your salvation dwell among us richly, and suffer not that trusty staff, the word of Your promise, to be taken from us. And when the shadow of death spreads over us, conduct us safely to the fold of perfected saints, the tabernacle not made with hands, eternal in the heavens. Amen.
(from Reading the Psalms with Luther, pgs. 59-60)