Psalm 86:16 O turn unto me, and have mercy unto me, give thy strength unto thy servant, and save the son of thine handmaid.
Proud and violent men are against David, but he responds by placing his trust in the Lord who is compassionate, and gracious, longsuffering, and plenteous in mercy and truth. Therefore, he knows he can ask God to turn to him, have mercy, give him His strength, and save him.
When we know who God is and what He thinks about us in mercy, we can trust Him to turn His love and attention toward us in the time of trouble (which is every day). To know what God thinks about us we only need to look to the suffering and death of the Son of God on the cross. We know Jesus and we believe God. We see His mercy in the Gospel. We receive and enjoy His love and forgiveness by faith in Jesus, who He is and what has done. Because of Christ, we are sure the Lord will see our present need, hear our prayer, give us strength, and save us. We can live lives of peace, joy, and thanksgiving.