What does Psalm 38:13 mean?

As David suffers due to sin (Psalm 38:1–4), he perceives that his enemies plot and scheme to destroy him (Psalm 38:12). In verses 13 and 14, David implies that he makes no response to these issues, at all. This silence might have been a symptom of David's convicted suffering (Psalm 38:8). His statement might mean that he wanted to reply, and to speak out against his attackers, but was not able.

The other possibility is that David chooses silence as a humble response to his sin (Psalm 38:18). Rather than trying to defend himself, he might be accepting that only the Lord could vindicate him. Of course, when one is truly guilty of sin, there may be natural consequences. Those might be legal, medical, or social. God might mercifully spare someone from those, but such is not guaranteed. He certainly promises to send conviction and discipline to His followers (Hebrews 12:5–11). Yet even in those cases, a person can rely on God to guide the results according to His will.

If a believer is falsely accused of a sin or crime, he can remain silent and trust the Lord to settle the matter. Romans 12:17 exhorts believers not to repay evil for evil. This does not guarantee that justice will be done in this life, yet God's justice is inevitable. The same passage instructs: "Beloved, never avenge yourselves, but leave it to the wrath of God, for it is written, 'Vengeance is mine. I will repay, says the Lord'" (Romans 12:19).

Peter addresses the subject of unjust earthly suffering. He comments, "If when you do good and suffer for it you endure, this is a gracious thing in the sight of God" (1 Peter 2:20). The next verse points to Jesus as the believers' example of suffering righteously. "When he was reviled, he did not revile in return; when he suffered, he did not threaten, but continued entrusting himself to him who judges justly" (1 Peter 2:23).