Summary: Now I lay me down to sleep, I pray the Lord my soul to keep. If I should die before I wake, I pray the Lord my soul to take. It was the first prayer that I learned--probably the first prayer you learned too. And not without reason. It's rhetorically sound, in that it makes good use of parallel structure and rhyme. It acknowledges the distance between God and the prayer that sociologists claim marks all human prayer. And it can be customized, or at least mine could, by adding the imperative "bless" at the end of the prayer and then listing those who needed blessing.
