1 Corinthians 5:12,13 - Joseph Benson’s Commentary on the Old and New Testaments

For, &c. I speak of Christians only: for what have I to do to judge them that are without Namely, heathen: do not ye judge them that are within? Ye, as well as I, judge those of your own community: them that are without, God judgeth The passing sentence on these God hath reserved to himself, and they shall not go unpunished, though they fall not under your censure. Therefore In consideration of this, both in one view and the other, let it be your immediate care, as you regard the peace of the church, and the safety of your own souls; to put away from among yourselves Speedily, and with all due solemnity; that wicked person Whom I have mentioned, and any others, whose characters may, like his, be scandalous and infections. The apostle is thought, by some, to have written this, and the preceding verse, to show the Corinthians the reason why, after commanding them to pass so severe a sentence on the man, he said nothing to them concerning the woman, who was guilty with him. The discipline of the church was not to be exercised on persons out of it. Hence it appears that this woman was a heathen.