I delight to do Your will, O my God, and Your law is within my heart.
David recognized that God was looking for more than just animal sacrifices. “Sacrifice and offering You did not desire” (Psalm 40:6). But God wants us to hear and understand His will—and to delight to do it!
God’s will is expressed in His law, and David set his heart and mind to remember and obey. Delighting in God’s will is God’s desire—it is what pleases Him. This is the “living sacrifice” that the apostle Paul wrote about in Romans 12:1-2.
The book of Hebrews shows that this verse was prophetic of the attitude of Jesus Christ (Hebrews 10:5-7).