SINCERITY, Servants must render honest service
Ephesians 6:5-7
5. Servants, be obedient to those who according to the flesh are your masters, with fear and trembling, in singleness of your heart, as to Christ;
6. not in the way of service only when eyes are on you, as men pleasers; but as servants of Christ, doing the will of God from the heart;
7. with good will doing service, as to the Lord, and not to men;