Only here in the New Testament. Not in classical Greek, nor in Septuagint, though the kindred adjective ἑτερόζυγος of a diverse kind, occurs Lev 19:19. Unequally gives an ambiguous sense. It is not inequality, but difference in kind, as is shown by the succeeding words. The suggestion was doubtless due to the prohibition in Deu 22:9, against yoking together two different animals. The reference is general, covering all forms of intimacy with the heathen, and not limited to marriage or to idolfeasts. The different shades of fellowship expressed by five different words in this and the two following verses are to be noted.
Fellowship (μετοχὴ)
Only here in the New Testament. The kindred verb μετέχω to be partaker is found only in Paul's epistles and in Hebrews: μέτοχος partner, partaker, only in Hebrews and Luk 5:7. Having part with is the corresponding English expression.
Lit., what sharing is there unto righteousness and lawlessness? Δικαιοσύνῃ righteousness, though the distinctively Pauline sense of righteousness by faith underlies it, is used in the general sense of rightness according to God's standard.