1 Corinthians 6:18

πᾶν ἁμάρτημα. This word signifies some particular error, ἁμαρτία the general tendency to error. See Arist. Nic. Eth. 1 Corinthians 6:8, VI. 8. It is remarkable that ἁμάρτημα is common in classical, rare in Biblical Greek. Precisely the reverse is the case with ἁμαρτία. And this because both the Law and the Gospel recognized sin as a principle. See 1 John 3:4; 1 John 5:17.

ἐκτὸς τοῦ σώματος. That is, every other sinful act which affects the body approaches it from without or affects particular members. But this sin takes the body itself as a whole and makes it an instrument of sin.

εἰς τὸ ἴδιον σῶμα ἁμαρτάνει. The precise meaning of ἁμαρτάνω is to miss the mark. Thus what is meant here is that one guilty of this sin runs counter to the fundamental laws impressed on the human body from the first. The sexes were created simply and solely with a view to the Divine institution of the family. The mutual affection of parents is absolutely necessary to the welfare of the family, and this, again, can only be secured by the exclusive and permanent character of the marriage relation. See Genesis 2:24. The formation, therefore, of any physical ties between the sexes, short of this exclusive and permanent one, is a violation of the first principles of human society. The Divine anger is therefore plainly manifested against those who do such things. See Romans 1:24; Romans 1:27-32. In particular, history shews abundantly that no sin has such power as licentiousness to dissolve the very framework of society, by loosening the bonds of mutual confidence and mutual respect on which that framework reposes.