What does Psalm 38:2 mean?

David felt the deep pain of God's discipline (Psalm 38:1). He compares the pain of God's correction to arrows penetrating deeply into his body. Furthermore, the discipline felt like God's hand had struck him. It's not clear what sin David is speaking of in this passage (Psalm 38:18), but it might have been his fall regarding Bathsheba (2 Samuel 12:7–9).

To be "disciplined" by the Lord for sin is a mark of belonging to God. Hebrews 12:7–8 declares: "It is for discipline that you have to endure. God is treating you as sons. For what son is there whom his father does not discipline? If you are left without discipline, in which all have participated, then you are illegitimate children and not sons." If sinning does not bother someone, it is a sure sign that he does not know God as his heavenly Father. David could not escape the pain of being disciplined. And yet, neither could he escape the fact that he belonged to God. In verse 15 he will address God as "O Lord my God."