Psalm 6:20-23 says,

My son, keep thy father's commandment, And forsake not the law of thy mother: Bind them (His words) continually upon thine heart, and tie them (His words) about thy neck. When thou goest, it (commandment or law) shall lead thee; When thou sleepest, it (commandment or law) shall keep thee; and when thou awakest, it (commandment or law) shall talk with thee. For the commandment is a lamp; and the law is light (torah); and reproofs of instruction (what is directed) are the way of life (life eternal)."