Notes on the Bible, by Albert Barnes, [1834], at sacred-texts.com
Leviticus Chapter 18
I am, the Lord your God - The frequent repetition of this formula in these parts of the Law may be intended to keep the Israelites in mind of their covenant with Yahweh in connection with the common affairs of life, in which they might be tempted to look at legal restrictions in a mere secular light.
See the Lev 18:24-30 note.
If a man keeps the "statutes" (i. e. the ordinances of Lev 18:4) and "judgments" of the divine law, he shall not be "cut off from his people" (compare Lev 18:29), he shall gain true life, the life which connects him with Yahweh through his obedience. See the margin reference and Luk 10:28; Rom 10:5; Gal 3:12.
Near of kin - See the margin. The term was evidently used to denote those only who came within certain limits of consanguinity, together with those who by affinity were regarded in the same relationship.
To uncover their nakedness - i. e. to have sexual intercourse. The immediate object of this law was to forbid incest.
Or - It might be rendered "and", or rather, even; that is, which belongs to both parents as being "one flesh" (Gen 2:24; compare Lev 18:8, Lev 18:14). These prohibitions are addressed to men.
Compare the case of Reuben, Gen 49:3-4. See Co1 5:1.
Thy sister - What was here spoken of was the distinguishing offence of the Egyptians.
Thy father's sister - The instance of Amram and Jochebed Exo 6:20 seems to show that marriage with an aunt was not considered wrong by the Israelites when they were in Egypt.
Thy brother's wife - That is, if she had children. See Deu 25:5. The law here expressed was broken by Antipas in his connection with Herodias Mat 14:3-4.
To vex her - literally, to "bind" or "pack together". The Jewish commentators illustrate this by the example of Leah and Rachel Gen 29:30.
Molech - See the note at Lev 20:2-5.
The land designed and consecrated for His people by Yahweh Lev 25:23 is here impersonated, and represented as vomiting forth its present inhabitants, in consequence of their indulgence in the abominations that have been mentioned. The iniquity of the Canaanites was now full. See Gen 15:16; compare Isa 24:1-6. The Israelites in this place, and throughout the chapter, are exhorted to a pure and holy life, on the ground that Yahweh, the Holy One, is their God and that they are His people. Compare Lev 19:2. It is upon this high sanction that they are peremptorily forbidden to defile themselves with the pollutions of the pagan. The only punishment here pronounced upon individual transgressors is, that they shall "bear their iniquity" and be "cut off from among their people." We must understand this latter phrase as expressing an "ipso facto" excommunication or outlawry, the divine Law pronouncing on the offender an immediate forfeiture of the privileges which belonged to him as one of the people in covenant with Yahweh. See Exo 31:14 note. The course which the Law here takes seems to be first to appeal to the conscience of the individual man on the ground of his relation to Yahweh, and then Lev. 20 to enact such penalties as the order of the state required, and as represented the collective conscience of the nation put into operation.