So far we have:
Psalm 1 and Proverbs 1:1-7
Psalm 2 and Proverbs 1:8-14
1. The heading of Psalm 3 suggests we read the words of this psalm against the backdrop of David the king as its author, at the time that he was fleeing his son Absalom. That is a generative way of reading the psalm, although the headings to the psalms were obviously added later than the writing of the psalms themselves. So we might read the psalm twice, once without thinking of the heading, then again in light of the heading. We will hear truths both ways.
2. In itself, this is the psalm of someone who is under fire from his enemies. Some classify it as a psalm of lament.
The enemies of the psalmist do not believe that God will deliver him, but he has confidence that God will. The Lord is a shield to him. "I will not fear though ten thousands assail me on every side" (3:6). "From the Lord comes deliverance" (3:8). The psalmist asks the LORD to strike his enemies on the jaw and to break the teeth of the wicked (3:7).
We can pray this psalm when we call on the LORD for help, even when our enemies are metaphorical (envy, jealousy, rage, depression).
3. Nothing internal to the psalm suggests inductively that it was written when David was fleeing Absalom. Indeed, the mention of God's holy mountain seems to allude to the temple, which was not build in the time of David. It suggests that the psalm dates subsequent to David.
Nevertheless, perhaps the story of David fleeing Absalom might give a certain concreteness to the psalm. We always connect better when we can picture a specific instance of the words, in this case Absalom chasing David. Of course fleeing is not mentioned in the psalm itself, and David would scarcely have prayed for God to break Absalom's teeth.
So the son is exhorted not to go along with the gangs that steal and shed blood. Those who live lives of violence set a trap for themselves. As Jesus would later say, "Those who live by the sword will die by the sword" (Matt. 26:52). Those who go after gain that is not theirs lose their lives. Christians might say in the next life if not in this one.