51:3 About a year had passed between David's sin of adultery and the time when he acknowledged his guilt. We know this because Bathsheba had given birth to the child she had conceived illegitimately when David confessed his sin (cf. 2 Sam. 12:13-18). David's sin had been on his mind for many months. Evidently he had hardened his heart and refused to admit that what he had done was sinful. Probably he had rationalized it somehow.
51:4 David had finally come to the place where he was willing not only to call his sin sin but to admit that it was sin against God primarily. Obviously he had sinned against Bathsheba and her husband, but David rightfully admitted that the worst thing he had done was offending God. He made no attempt to blame God for what had happened. He took full responsibility himself. He acknowledged that his Judge was guiltless and that he was guilty. Taking personal responsibility for our sins is an important part of true confession.
"To say Against thee, thee only, have I sinned' may invite the quibble that adultery and murder are hardly private wrongs. But it is a typically biblical way of going to the heart of the matter. Sin can be against oneself (I Cor. 6:18) and against one's neighbour; but the flouting of God is always the length and breadth of it, as Joseph saw long before (Gn. 39:9)."113
51:5 The king went on to confess the depth of his sinfulness. He had been a sinner from the time he came into existence as a human being, namely at his conception. This is one of the strongest indications in the Bible that human life begins at conception rather than at birth (cf. 139:13-16). He viewed sinful acts as the fruit of a sinful nature, not as the product of his environment or the situation that had triggered his acts. This verse does not mean David felt free of personal responsibility for his actions. He felt responsible as is clear from his statements in the context.
51:6 David also realized God wanted him to be completely honest, not just to offer an offering. He needed to get his heart right with God. His confession had to be genuine rather than the superficial repetition of some words. Wisdom in the Old Testament refers to living life in the light of God's presence and revelation. God wants people to be completely honest with Him and to deal with reality. David acknowledged this.
