When David wrote this Psalm, he had been driven from his throne. His son Absalom rose up and, by saying what people wanted to hear, turned Israel against their king. His father left the Holy City downcast. Friends wept as enemies fired mud.
As the Psalm begins many enemies crowd round David. They say that God can’t save. The king is finished. He has no hope. Now he prays to God & tells him all is troubles. When the chips are down & everything is against us, we too must cry to God.
David trusts in God for safety and protection. He says ‘You are my shield’. He knows he’ll be OK. He remembers how Abram had fought off 5 great kings. After battle God spoke: ‘I am your shield.’ He prays to God’s House. You too expect defence.
He’s starting to feel sleepy. He’s not afraid to lie down sweetly. Though many could attack, God will guard him till he wakes. David leans on God as he prays this lullaby. His God-crutch won’t give way. He & we need not be afraid of those around.
These enemies are wolves. David sees their snarling fangs. These are deadly weapons. He wants their teeth disarmed. That’s why he prays smash their teeth & jaw. He’s not getting mad. He just wants to be safe. If God saves then he will do that.
Jesus prayed Psalm 3 many times. As he turned lights out, His Father gave Him sleep. All Jerusalem rose up & drove Jesus outside city gates. He went to sleep on the Cross. He rose up from the grave. So we can pray Psalm 3 & wake up after death.