What does Psalm 24:1 mean?

This psalm is credited to David. It is possible, even likely, that this was composed to celebrate the return of the ark of the covenant from Obed-edom's house (2 Samuel 6). This is not certain, however.

Abraham referred to the Lord as "Possessor of heaven and earth" (Genesis 14:22). In Psalm 24:1 David affirms the truth that the Lord owns all creation. He states that the earth and everything pertaining to it, including human beings, belongs to the Lord. Although God placed a curse on the earth following our first parents' sin, the Lord possesses the earth and everything in and on it, and when Jesus returns to earth, he will roll back the curse and restore earth to Edenic conditions (see Genesis 3; Isaiah 11:1–16; Romans 8:19–21).

David also acknowledges that God owns all human beings. The term translated "fullness" here is meant as a reference to all people. Genesis 1:26–27 reports that God created humanity, as males and females, in His own image. First John 2:2 declares that Jesus Christ died for the sins of all mankind. Therefore, the Lord has a rightful claim to our lives by virtue of creation and redemption.