And whatsoever ye do,.... Some have thought that these words, and the two following verses, regard the Colossians in general, and the performance of any, and all good works by them; but by their connection with the preceding verse, and with the beginning of the next chapter, they appear to concern servants only, and what they do under that character, and under the discharge of their duty:
do it heartily, not by mere force and necessity, grudgingly, and with murmurings, but from the heart, and with good will, having a true, real, and hearty affection for their masters, having their good and interest at heart, and a delight in their service; like the Hebrew servant, that loved his master, as also his wife and children, and therefore would not depart from him, see Exodus 21:5,
as to the Lord, and not unto men; See Gill on Ephesians 6:7.

And--omitted in the oldest manuscripts (compare Ephesians 6:7-8). Compare the same principle in the case of all men, Hezekiah (2-Chronicles 31:21; Romans 12:11).
do, do it--two distinct Greek verbs, "Whatsoever ye do, work at it" (or "labor at" it).
heartily--not from servile constraint, but with hearty good will.

Heartily - Cheerfully, diligently. Menpleasers are soon dejected and made angry: the single - hearted are never displeased or disappointed; because they have another aim, which the good or evil treatment of those they serve cannot disappoint.