What does Psalm 103:3 mean?

In this verse David begins to list some of the Lord's benefits for which He is worthy of praise. The first is forgiveness of all iniquity. The Hebrew word translated "iniquity" identifies something twisted and distorted. Lust, including lust for power or wealth, tries to convince us that sin is desirable, with a corrupted, warped perspective (James 1:14–15).

Iniquity brings conviction and judgment. Paul described a self-indulgent person as "dead even while she lives" (1 Timothy 5:6). David saw the sinful act of adultery as something desirable at first, but later his iniquity gnawed at him until he confessed it to the Lord and received forgiveness (Psalm 51:1, 8–12). In Psalm 103:3 David also praises the Lord for healing. Some illness comes by nature, not by sin, and God sometimes heals those (John 9:1–7). Often, however, it is sinning which brings sickness upon the sinner. Sometimes, but not always, when the Lord forgives sin He heals the sickness. Psalm 51:6 and Psalm 32:3–4 depict physical suffering that David's sin had brought upon him, but the Lord restored him spiritually and physically (Psalm 32:5–7).