Work heartily for the Lord

“Whatever you do, work heartily, as for the Lord and not for men.” (Col. 3:23 ESV)

Heartily: sincerely, genuinely, warmly, profoundly, with all one's heart.

“Whatever your hand finds to do, do it with all your might, for in the realm of the dead, where you are going, there is neither working nor planning nor knowledge nor wisdom.” (Eccles. 9:10 NIV)

Be fervent in spirit

“Do not be slothful in zeal, be fervent in spirit, serve the Lord.” (Rom. 12:11 ESV)

Therefore…

“Rendering service with a good will as to the Lord and not to man, knowing that whatever good anyone does, this he will receive back from the Lord, whether he is a slave or free.” (Eph. 6:7-8 ESV)