Ephesians 5:11

Have no fellowship - Have no religious connection whatever with heathens or their worship.

Unfruitful works of darkness - Probably alluding to the mysteries among the heathens, and the different lustrations and rites through which the initiated went in the caves and dark recesses where these mysteries were celebrated; all which he denominates works of darkness, because they were destitute of true wisdom; and unfruitful works, because they were of no use to mankind; the initiated being obliged, on pain of death, to keep secret what they had seen, heard, and done: hence they were called απορῥητα μυστηρια, unspeakable mysteries - things that were not to be divulged. That the apostle may refer to magic and incantations is also probable, for to these the Ephesians were greatly addicted. See the proofs in the notes on Acts 19:19.

Rather reprove them - Bear a testimony against them; convince them that they are wrong; confute them in their vain reasons; reprove them for their vices, which are flagrant, while pretending to superior illumination. All these meanings has the Greek word ελεγχω, which we generally render to convince or reprove.

And have no fellowship - See the sentiment here expressed fully explained in the notes on 2 Corinthians 6:14-18.

The unfruitful works - The deeds of darkness that produce no "benefit" to the body or the soul. The word "unfruitful" is used here in contrast with the "fruit of the Spirit," Ephesians 5:9.

But rather reprove them - By your life, your conversation, and all your influence. This is the business of Christians. Their lives should be a standing rebuke of a sinful world, and they should be ever ready to express their disapprobation of its wickedness in every form.

5:11 Reprove them - To avoid them is not enough.