Because God had initiated love toward Israel by redeeming the nation (v. 6) the people were to respond appropriately by loving Him in return. This is the essence of God's grace. He initiates love, and the only reasonable response is to love Him for what He has done (cf. Rom. 12:1-2). God does not just love us when we love Him. More fundamentally, He loves us first (cf. Rom. 5:10; Eph. 1:4-5; 1 John 4:19).
This command was a call to respond to God's love by remaining faithful to Him instead of turning from Him to love something else more than Him. Israel was to have no other gods before or beside Yahweh. The people were to worship Him exclusively.75
This commandment applies to all people, not just Israel. Yahweh is the only true God worthy of love and worship for who He is and what He has done. He has reached out lovingly to all humankind with the provision of salvation (cf. Acts 14:15; 1 Cor. 10:31; 1 Tim. 2:5; James 2:19; 1 John 5:20-21). The writer's view of the earth as having living beings above the earth, on the earth, and under the water of the earth is consistent with all ancient Near Eastern cosmology (cf. Gen. 1).76