David is blessed by God.
Arise, O LORD;
Save me, O my God!
For You have struck all my enemies on the cheekbone;
You have broken the teeth of the ungodly.
Salvation belongs to the LORD.
Your blessing is upon Your people. Selah
David's mind was on two things.
Save me, O my God
struck all my enemies … broken the teeth of the ungodly
In knowing what The Lord God has done gave David confidence in what The Lord God would do.
If we look at the words of Numbers 10:35, we see that Moses used this phrase as the children of Israel broke camp in the wilderness. This phrase was a military phrase, calling on The Lord to go forth and do two things...
Defend Israel
Lead them to victory
Broken the teeth of the ungodly.
In Psalm 58:6 we also see this vivid metaphor being used. It speaks of the total defeat and the total domination of the enemy. In this Psalm David looked for protection, but more than this he looked for victory. For David to survive the threat to the kingsom wasn't enough. Over the htreat he had to be victorious, and he would with the blessing of The Lord.
Salvation, both in the immediate and ultimate sense, was The Lord's property, and David understood this. It is not the property of anyone else or any other nation. It is God's property. One must deal with God Himself to be saved.
In a time of personal calamity David's heart was shown. God's hand upon himself wasn't his only concern. He was also concerned about God's hand upon all God's people. In the trial with Absalom David didn't pray for victory and preservation just for his own sake, but he did it because it was best for the nation.