What does Psalm 30:2 mean?

God punished David for taking an improper census (1 Chronicles 21:7–30). God graciously allowed David to avoid greater punishment—defeat by his enemies—and to instead suffer a plague on Israel (1 Chronicles 21:7–14). At one point during the pestilence, David cried out for God's mercy, and the Lord stopped the disease (1 Chronicles 21:15–17). The context of this psalm seems to be what happened shortly after the plague was lifted: David's dedication (Psalm 30:1) of the future temple site (1 Chronicles 22:1; 2 Chronicles 3:1).

Neither David's sin, nor God's discipline, separated David from the Lord's love. A believer may wander from fellowship with the Lord, but he still belongs to the Lord. He is like the sheep that wandered from the fold. It still belonged to the shepherd, who searched for it, found it, carried it on his shoulders, rejoiced, and returned it to the fold (Luke 15:4–6).

God's ability to heal is also celebrated here. Paul explains to the Corinthians why some members of the church were ill and dying. He attributes the sickness and death to a specific sin, which was partaking of the Lord's Supper in an unworthy manner. That does not mean all sickness is caused by sin (John 9:1–3), but it does mean God can use illness as one of His forms of discipline. A believer may sin willfully and suffer consequences, but if he repents and calls upon the Lord for healing, the Lord may remove the sickness and forgive the sin. James 5:13–16 discusses this type of situation and directs the sick person to call for the elders of the church. He will be healed upon confessing his sins and receiving prayer.