When Jesus returns at His second advent, He returns as king. Revelation 19:16, "And he hath on his vesture and on his thigh a name written, KING OF KINGS, AND LORD OF LORDS." Additionally, when He resurrects the saints, He makes them kings with Him. Revelation 1:5,6, "…him (Jesus) that loved us, and washed us from our sins in his own blood, And hath made us kings and priests unto God and his Father…" As God's representative kings, Jesus and His saints will resurrect all mankind (John 5:28,29) and teach them God's law of love and justice. Jeremiah 31:33, 34, “I will put my law in their minds and write it on their hearts. I will be their God, and they will be my people. No longer will they teach their neighbor, or say to one another, ‘Know the LORD,’ because they will all know me, from the least of them to the greatest,” declares the LORD. “For I will forgive their wickedness and will remember their sins no more.”
When Christ has finished the great work of restoring mankind and earth back to perfection, then Jesus will turn this wonderful earth back to God, the Great King. 1 Corinthians 15:24, 25, 28, "Then cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power. For he must reign, till he hath put all enemies under his feet…And when all things shall be subdued unto him, then shall the Son also himself be subject unto him that put all things under him, that God may be all in all."