“and all it contains.” The Hebrew is very succinct, “and its fullness,” that is, “and everything that fills it,” or more clearly in English, “everything it contains” (cp. NASB; NET; NJB). The earth and everything in it ultimately belongs to Yahweh. That we humans actually own anything is a hoax, a mirage. Ecclesiastes 5:15 and 1 Timothy 6:7 say that we did not bring anything into the world when we were born and we cannot take anything with us when we die. Everything we have on earth is borrowed from God. That is why wise believers obey God on earth and build rewards that will be given to them in the next life.
[For more on rewards in the future Kingdom of Christ on earth, see commentary on 2 Cor. 5:10, “good or evil.”]