23 And whatever you do, do it heartily, as to the Lord and not to men,
24 knowing that from the Lord you will receive the reward of the inheritance; for you serve the Lord Christ.
25 But he who does wrong will be repaid for what he has done, and there is no partiality.
and (v.23) — This ties in with verse 22 and specifically “fearing God” from that verse.
do (v.23 — 1st use) = poieo — mere doing
do (v.23 — 2nd use) = ergazomai — labor, do diligently
heartily (v.23) = out of the soul
knowing (v.24) = being fully aware
receive (v.24) = receive as one’s due
reward (v.24) = a due return, recompense — not “reward”
inheritance (v.24) — not in the usual sense, but “a sanctioned, settled possession”
He who does wrong (v.25) — The reference is primarily to the slave; but the following clause extends it to the master. If the slave do wrong, he shall be punished; but the master who does wrong will not be excused; for there is no respect of persons. Tychicus, who carried this letter to Colossae, carried at the same time the letter to Philemon, and escorted Onesimus to his master.
The recent fault of Onesimus would make the apostle doubly anxious to emphasize the duties of the slave towards the master, lest in his love for the offender, he should seem to condone the offence. But on the other hand, it is the apostle’s business to show that justice has a double edge. There must be a reciprocity between the master and the slave. The philosophes of Greece taught, and the laws of Rome assumed, that the slave was a chattel. But a chattel could have no rights. It would be absurd to talk of treating a chattel with justice. Paul places the relations of the master and the slave in a wholly different light. Justice and equity are the expression of the Divine Mind. and with God there is no respect of persons. With Him the claims of the slave are as real as the claims of the master. — Ephesians and Colossians, by Kenneth S. Wuest, pages 231-232.
These verses are directed to slaves, urging them to do all their work as if they were doing it directly for the Lord. They may not get payment for their work on earth, but they will in heaven. Also, they should not presume that their position in Christ will allow them to disobey their masters without penalty.