Arise, O LORD! Save me, O my God! For you strike all my enemies on the cheek; you break the teeth of the wicked.  Salvation belongs to the LORD; your blessing be on your people! Selah (ESV)
As we conclude this Psalm of David we find him in his final cry for God to save him from his enemies, the first of which was his son, Absalom. He recognizes that it is God who will fight his battles for him. God is the one who strikes all his enemies, breaking the teeth of the wicked. We know that God rescued David from his enemies. Here is an account of Absalom's death:
2 Samuel 18:14–15
 Joab said, “I will not waste time like this with you.” And he took three javelins in his hand and thrust them into the heart of Absalom while he was still alive in the oak.  And ten young men, Joab's armor-bearers, surrounded Absalom and struck him and killed him. (ESV)
We do not always know exactly how God is going to bring victory to us, but we know that we can count on him to always save us. Salvation belongs to the Lord. The problem with many of us is that we try to save ourselves and get God to approve of what we have done. We need to recognize that God's means of salvation for us is best. Maybe that salvation will be realized in this life. Maybe the next.
What are you struggling with? Are your enemies overwhelming you? Maybe those enemies are the voices of past failings. Maybe they are current mockers. Cry out to God. He is your salvation.