Isn't Paul slandering the Old Testament by saying in Hebrews 7:18-19, 8:13 that the Law is obsolete and weak, contradicting Psalm 19:7 which states the Law is perfect?

Paul's statements in Hebrews about the Law being obsolete do not contradict the assertion that the Law is perfect as stated in Psalm 19:7. Instead, Paul emphasizes that the Law, while good, is rendered ineffective by human wickedness. In Romans 3:10-20, Paul explains that the Law speaks to those under it to hold them accountable to God, revealing their sinfulness. He further clarifies in Romans 7:7-14 that the Law itself is holy, righteous, and good, but it is sin that produces death through the commandment. Therefore, the Law's purpose is to expose sin and demonstrate humanity's need for redemption. This is why God sent Jesus, so that through His sacrifice, believers can be freed from the Law's condemnation and live in the newness of the Spirit, as outlined in Romans 7:4-6.