What does Psalm 33:1 mean?

The psalmist, likely David, is worshiping, and he calls upon his fellow believers to shout in joyful praise to the Lord. He exclaims that praise is appropriate—God is certainly worthy of approval. In a biblical context, only righteous people can possess true joy. This does not require moral perfection. Rather, it means a person who diligently seeks God's will and doesn't openly defy Him (Matthew 6:33). Hearts out of tune with the Lord cannot sing beautiful praise to Him or offer suitable praise.

In his life, David experienced many victories over his enemies. He had deep, personal reasons to call on the congregation to shout for joy. Even for faithful believers, life can be hard (John 16:33). The Lord's people may not see anything to be joyful about in their surrounding circumstances. And yet, there are many reasons to be joyful despite those hardships, because they are God's people (Romans 8:18). In his letter to the Philippians, Paul wrote about joy in the Lord, often noting that he rejoices (Philippians 1:18; 2:17–18). He encourages the Philippian believers to rejoice in the Lord and repeats this appeal (Philippians 4:4).