When thou goest, it shall lead thee; when thou sleepest, it shall keep thee; and when thou awakest, it shall talk with thee. When thou goest, it shall lead thee - Here the law is personified; and is represented as a nurse, teacher, and guardian, by night and day. An upright man never goes but as directed by God's word and led by God's Spirit.
When thou sleepest - He commends his body and soul to the protection of his Maker when he lies down and sleeps in peace. And when he awakes in the morning, the promises and mercies of God are the first things that present themselves to his recollection.