Summary: Saved from Saul, David rejoices in God's protection. This is a very long psalm, so let's have a look; David calls God:
Source of strength, high ridge, stronghold, deliverer, rocky summit, shield, horn (like the attacking kind), refuge, lamp, protector, king; worthy of praise, sovereign, loyal, reliable, trustworthy, true, alive, praiseworthy, faithful.
He also recounts (again) God's might, his innocence, his enemies' guilt, and what he got God to do to his enemies.
Response: God, I know you are protecting me from things all the time. But I don't think any of them are individuals who want my death. Thank you for your protection, but be with my enemies; I really do feel I want them to succeed. Not in hurting me, of course, but in becoming better people, drawn closer to you, maybe through me.