Throughout this verse, David expresses his gratitude to the Lord for delivering him from the Philistines, and he invites others to share his joy in singing to the Lord with him. Despite being a champion warrior who had survived several battles, David remained humble. In addition, he did not boast about his recent escape from the Philistines at Gath. In contrast, he boasted about Christ, encouraging the humble to rejoice as he sang praises to the Lord.
As fallen sinners, we are a part of the sinful race of humanity and have nothing to boast about. As a result of our sins, we were born dead and are estranged from the God who created us. The glory of God is so far beyond what we can comprehend that we should never allow prideful boasting and an inflated ego to enter into our imaginations. Each of us can, however, find glory in one area - and that is in the redeeming blood of Christ our Savior.
The Lord forgives every one of our iniquities and heals every illness that we suffer. Through His lovingkindness, He has redeemed our life from death and corruption. He provides us with all our daily needs as well as executes righteousness and justice. We have nothing to boast about when it comes to our souls. It is, however, to the Lord that we will make our boast.

Dear Heavenly Father, it is a great privilege to be a member of Your family and receive salvation by grace through faith in the shed blood of our great God and Redeemer. You have made me a new creation in Christ and blessed me with the joy of being part of Your family for eternity. From this day forward, I pray with humility of heart and overwhelming gratitude to glory only in Jesus Christ and His righteousness. 
In Jesus's name I pray. Amen.