And have no fellowship with the unfruitful works of darkness, but rather reprove them.
Unfruitful works of darkness. Sins, being terminated in themselves, are called "works," not 'fruits' (Galatians 5:19; Galatians 5:22). Their only fruit, (if the term is to be used) (Deuteronomy 32:32) is "death" (Romans 6:21; Galatians 6:8). Plants cannot bear "fruit" in the absence of light. Sin is "darkness;" its parent the prince of darkness, (Ephesians 6:12). Graces, as flourishing in "the light," are reproductive, and abound in fruits; which, as harmoniously combining in one whole, are singular - "the FRUIT of the Spirit" (Ephesians 5:9).
Rather ... - Greek, 'rather, even reprove them' (cf. Matthew 5:14-16). Not only 'have no fellowship, but even reprove them,' in words (Ephesians 5:13; 1 Corinthians 14:24; Titus 1:13; Titus 2:15). Not that we can be avoid all contact (1 Corinthians 5:10), but 'avoid such fellowship as will defile you;' just as light, though it touch filth, is not soiled by it; nay, as light detects it, so 'even reprove sin.'