Answer: Children of God ARE serving the Lord, (verse 24).
MORE INFORMATION AND/OR OTHER SCRIPTURE REFERENCES:
In Matthew 4:10 and Luke 4:8, Jesus told Satan Who we serve: "Jesus said to him, ‘Away from me, Satan! For it is written: "Worship the Lord your God, and serve Him only."'"
Ephesians 6:7-8: "Serve wholeheartedly, as if you were serving the Lord, not men, because you know that the Lord will reward everyone for whatever good he does, whether he is slave or free."