2 Samuel 22-24: The Source of Greatness.

David was a mighty warrior, and he was surrounded by mighty fighting men as well.  But David knew that his strength was not from the mighty men.  His strength came from the rock, his fortress, and his deliverer.  Without God, David would have just been another fighter.  He might have resembled Goliath, who felt he was entitled to hurl insults at the enemy because of his size.  He might have been like Saul, who led the Israelites in victory, but spent most of his days comparing his exploits to those of David.  He might have been like Absalom, creating a powerful coalition by means of subterfuge.  But instead David's song acknowledges the source of his strength and success.

 "As for God, his way is perfect;
the word of the LORD is flawless.

He is a shield
for all who take refuge in him.

For who is God besides the LORD ?
And who is the Rock except our God?

It is God who arms me with strength
and makes my way perfect.

He makes my feet like the feet of a deer;
he enables me to stand on the heights.

He trains my hands for battle;
my arms can bend a bow of bronze.

You give me your shield of victory;
you stoop down to make me great."
2 Samuel 22:31-36

David never ceased to recognize and praise the source of his strength; the source of his very being.  That is what made him great.  He never ceased to recognize the source of his perfection.  That is what made him righteous.