Vs. 1-5 as in Psalm 3, places the proper response to one’s enemies into the hand of God;
Vs. 6-8 show the peacefulness that permits God’s person to slumber safely.
The command, “Be angry, and do not sin” is exactly quoted in Ephesians 4:26 as inspired advice for human passion, but the New Testament adds the extra step of resolving anger before the day is over (Ephesians 4:26) and it becomes “wrath” and gives “place to the devil” (Ephesians 4:27).
Psalm 3:5 and 4:8 may well have been the beginning of the child’s prayer, “Now I lay me down to sleep, I pray the Lord my soul to keep.” Certainly the contentment of a child should be in the heart of any adult who would commit his/her soul into the hand of God because of obedience to His word. This truth was included in the Wisdom of Solomon in Proverbs 3:24: “When you lie down, you will not be afraid; Yes, you will lie down and your sleep will be sweet” (Proverbs 3:21-26). This reassurance for the faithful in Jesus Christ in the New Testament says: “For God did not appoint us to wrath, but to obtain salvation through our Lord Jesus Christ, 10 who died for us, that whether we wake or sleep, we should live together with Him. 11 Therefore comfort each other and edify one another, just as you also are doing” (1 Thessalonians 5:9-11).