‘…his delight is in the law of the LORD…’ (Psalm 1:2)
Though this certainly means delighting in his word as a whole, this verse gives specific reference to the law. The blessed one of God, the one in God’s favor, delights in the commandments of God and doing them, for it is to this he has been saved. For the one blessed of God, no longer is obedience a burdensome task of trying to find acceptance with Him (justification) since that has already been obtained through Christ and His work through faith, granted as a gift. Christ has provided the righteousness necessary to stand in the Father’s presence, out of His sheer mercy. But now, having been accepted, obedience stems from the joy of the believers heart, because of God’s work on his behalf. The one in God’s favor delights in obedience out of the overflow of His heart.