For whosoever shall commit any of these abominations, even the souls that commit them shall {p} be cut off from among their people.

(p) Either by the civil sword or by some plague that God will send upon such.

Wesley's Notes

18:29 Cut off - This phrase therefore of cutting off, is to be understood variously, either of ecclesiastical, or civil punishment, according to the differing natures of the offences for which it is inflicted.

Jamieson-Fausset-Brown Bible Commentary

29. the souls that commit them shall be cut off-This strong denunciatory language is applied to all the crimes specified in the chapter without distinction: to incest as truly as to bestiality, and to the eleven cases of affinity [Le 18:7-16], as fully as to the six of consanguinity [Le 18:17-20]. Death is the punishment sternly denounced against all of them. No language could be more explicit or universal; none could more strongly indicate intense loathing and abhorrence.

Matthew Henry's Concise Commentary

18:1-30 Unlawful marriages and fleshly lusts. - Here is a law against all conformity to the corrupt usages of the heathen. Also laws against incest, against brutal lusts, and barbarous idolatries; and the enforcement of these laws from the ruin of the Canaanites. God here gives moral precepts. Close and constant adherence to God's ordinances is the most effectual preservative from gross sin. The grace of God only will secure us; that grace is to be expected only in the use of the means of grace. Nor does He ever leave any to their hearts' lusts, till they have left him and his services.