2 Samuel 21-22 David is getting physically weaker, but spiritually stronger.  His last battle is again with the Philistines and the giants of Gath, just as his first battle was.   This time though, others slayed the giants.  

David's psalm is recorded here and in Psalm 18.  David makes clear his confession by declaring that God is:  
His rock.
His fortress.
His deliverer.
His God.
His refuge.
His shield.
The horn of His salvation.
His stronghold.
His refuge.
His savior.
His support.
His lamp.
His tower. 

David called on the Lord, he obeyed the Word of the Lord,  he worshipped the Lord, and He gave thanks to the Lord.  All through this journey that David has taken, from shepherd boy to king of Israel, David has clung to and trusted in the Lord.  He takes no honor or credit for his own actions, but gives all glory to God.
" He heard my voice."
" He bowed the heavens and came down.." 
" He rescued me.."
It is God who executed vengeance and brought down nations.  It is God who showed lovingkindness to David.

Father in heaven,  You are the same with each of us as You were with David.  You alone are our hope and salvation, our refuge and deliverer.  Thank You for showing lovingkindness to us also. Thank you for hearing our calls for help and for leading us in Your ways.  Be our rock and salvation forever.  Be glorified about all the earth, for You alone are God.  Our God, our help in ages past, our help in the days to come.  Fill us with Your Spirit once again that we might serve You fully.  In the Name of Jesus we pray, amen.