Ephesians 6:5 commands slaves to obey as to Christ — providing the foundation for the attitude of good will in verse 7.

Ephesians 6:6 contrasts eye-service with wholehearted service — verse 7 then encourages serving with good will.

In 1 Corinthians 10:31, doing all to God's glory applies the same principle to every action, including service.

Colossians 3:23 gives the near-identical instruction to work heartily for the Lord — reinforcing the call to serve with good will.