Psalms 51:5

Behold, I was shapen in iniquity; and in sin did my mother conceive me.

This is part of David's prayer and confession of repentance after his fall and great sin and departure from righteousness, spoken when he was convicted by God's message of reproof and sharp rebuke. It expresses sincere and deep sorrow for sin, remorse and self-loathing, a contrite and humble spirit, and penitence turning to God for mercy, pardon, cleansing and purity. Within that prayer it is the acknowledgment of transgression with sin ever before him and confession of inborn sinfulness, amid pleading for mercy according to loving-kindness and tender mercies, for transgressions to be blotted out and for thorough washing and cleansing from iniquity and sin. It seeks purging with hyssop to be clean and white as snow, hearing joy and gladness so broken bones rejoice, God's face hidden from sins with iniquities blotted out, creation of a clean heart and renewal of a right spirit, not being cast from God's presence nor losing the Holy Spirit, restoration of the joy of salvation and upholding by God's free Spirit, then teaching transgressors God's ways so sinners are converted, and deliverance from blood-guiltiness so the tongue sings of God's righteousness.

It teaches that people are born in sin and inherit Adam's sinful nature, with no natural goodness of their own. Seth, like Cain, was born in sin with no more natural goodness than Cain, and though a worthy man who chose to honor God and do right, he did so through God's grace and the faithful instruction he received from Adam. It shows that the natural heart has strong inclinations to sin, which God fully knows, so He hears prayer and helps in every time of temptation.

David's response shows a beloved character not because he was perfect but because he did not cherish stubborn resistance to God's expressed will nor rise in rebellion against reproof. He bowed under chastisement and was humbled as greatly as he had erred, with contrition as profound as his guilt, showing strength not in always resisting temptation but in sincere penitence. He kept confidence in God who spoke through the prophet, felt no hatred for the prophet, relied on the mercy of the God he loved and served, loved much because he was much forgiven, refused counsel with men sinning against God, trusted God more than man, and accepted God's decision as just and merciful. The confession was left as a sacred song recounting his sin, his repentance, and his hope of pardon through the mercy of God. Instead of concealing his guilt, it was given to be sung in the public assemblies of Israel in the presence of priests and judges, princes and men of war, to preserve the knowledge of his fall to the latest generation and to instruct others by the sad history of his fall.

David was convicted of his wrongdoing, repented with genuine repentance toward God and faith in Jesus Christ, and found pardon through Christ. Though he suffered for his transgression, his repentance was accepted by God, who forgave him and took him into covenant relation with Himself. The verse therefore means that when a person has fallen into sin he must seek God without delay for mercy and pardon in penitence and humiliation, as David did when convicted, feeling that he could endure the loss of his crown but could not be deprived of the favor of God. Mercy is still extended to the sinner, and God calls wanderers and backsliding children to return so He can heal their backslidings, with blessing coming to those who heed the pleading voice of His Spirit, for like a father He pities those who fear Him. This brings encouragement to souls fallen into sin and struggling under guilt and ready to give up to despair, leading thousands of God's children betrayed into sin to take courage, repent, try again, and walk in the way of God's commandments.