Commenting on these words, Spurgeon wrote:
David's great needs required a bountiful provision, and his little desert could never give such a supply. Thus, he throws himself on God's grace and looks to the Lord and His great goodness for the great things he needs. He begs for heavy grace, like the one who prayed, "Oh, Lord, You must give me great mercy, or no mercy, for little mercy will not help me!"
Charles Spurgeon, Beside Still Waters, Ed. Roy H. Clarke (Nashville: Thomas Nelson, 1999), 102.