51:7 Again David pleaded for purification and cleansing (vv. 1-2). In Israel the priest sprinkled animal blood on the altar with a hyssop branch. This ritual symbolized cleansing by sacrificial death (cf. Heb. 9:22). If God would wash David morally, he would be thoroughly clean.
51:8 This verse is a request for renewed joy. David's fractured relationship with God pained him as much as a broken bone (cf. 6:2).
51:9 The expressions in this verse picture God like a judge removing David's sins. The psalmist wanted God to put his sins in a place where He would not see them and to blot out any record of them from His books.
51:10 The psalmist's petition now turned to thoughts of spiritual renewal. In contrast to his natural sinful heart (v. 5), David sensed the need for a clean heart. He requested a spirit more faithful to the Lord than his natural spirit (inclination) to depart from the Lord.
51:11 Casting away from God's presence implies a rejection as God's servant. Saul had suffered such a fate for his continuing rebellion against Yahweh. In Old Testament times God gave His Holy Spirit selectively (to empower only some believers) and temporarily (primarily to empower them for special acts of service). Since the day of Pentecost all believers enjoy the permanent indwelling of the Holy Spirit (John 14:17; Rom. 8:9). Consequently the possibility of God's withdrawing His Spirit from David was a real one for him, but it is not for us.114It is possible that a Christian may lose his or her opportunities to serve the Lord, however (1 Cor. 9:27). For example, a Christian who gets involved in gross sin will not lose his or her salvation (John 10:28-29), but he or she may lose the opportunity to serve God in a leadership capacity.
51:12 Again David asked for renewed joy (cf. v. 8). He had not lost his salvation as a result of his sin, but he had lost the joy of it. The Lord was apparently not delivering him from his present distresses as He had done previously. He also requested a cooperative spirit, one that would cooperate with God and thereby sustain himself.
