21 " 'Do not give any of your children to be sacrificed to Molek, for you must not profane the name of your God. I am the Lord.
2 "Say to the Israelites: 'Any Israelite or any foreigner residing in Israel who sacrifices any of his children to Molek is to be put to death. The members of the community are to stone him. 3 I myself will set my face against him and will cut him off from his people; for by sacrificing his children to Molek, he has defiled my sanctuary and profaned my holy name. 4 If the members of the community close their eyes when that man sacrifices one of his children to Molek and if they fail to put him to death, 5 I myself will set my face against him and his family and will cut them off from their people together with all who follow him in prostituting themselves to Molek.
(Read Leviticus 20:1-9)
Are we shocked at the unnatural cruelty of the ancient idolaters in sacrificing their children? We may justly be so. But are there not very many parents, who, by bad teaching and wicked examples, and by the mysteries of iniquity which they show their children, devote them to the service of Satan, and forward their everlasting ruin, in a manner even more to be lamented? What an account must such parents render to God, and what a meeting will they have with their children at the day of judgment! On the other hand, let children remember that he who cursed father or mother was surely put to death. This law Christ confirmed. Laws which were made before are repeated, and penalties annexed to them. If men will not avoid evil practices, because the law has made these practices sin, and it is right that we go on that principle, surely they should avoid them when the law has made them death, from a principle of self-preservation. In the midst of these laws comes in a general charge, Sanctify yourselves, and be ye holy. It is the Lord that sanctifies, and his work will be done, though it be difficult. Yet his grace is so far from doing away our endeavours, that it strongly encourages them. Work out your salvation, for it is God that worketh in you.
10 Let no one be found among you who sacrifices their son or daughter in the fire, who practices divination or sorcery, interprets omens, engages in witchcraft,
(Read Deuteronomy 18:9-14)
Was it possible that a people so blessed with Divine institutions, should ever be in any danger of making those their teachers whom God had made their captives? They were in danger; therefore, after many like cautions, they are charged not to do after the abominations of the nations of Canaan. All reckoning of lucky or unlucky days, all charms for diseases, all amulets or spells to prevent evil, fortune-telling, &c. are here forbidden. These are so wicked as to be a chief cause of the rooting out of the Canaanites. It is amazing to think that there should be any pretenders of this kind in such a land, and day of light, as we live in. They are mere impostors who blind and cheat their followers.
Matthew Henry's Commentary on Leviticus 18:21
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.