The crimes which are condemned in Leviticus 18; 19 on purely spiritual ground, have here special punishments allotted to them as offences against the well-being of the nation.
Matthew Henry
Concise Bible Commentary
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.
SDA Bible Commentary (limited)
Volume 1-7
1. The Lord spake. Most of the offenses mentioned in this chaper have been discussed in chs.18 and 19. There the appeal to the people was purely on spiritualgrounds, an appeal to their sense of right. Here, the offenses are considered as crimes against the state, and hence punishable. The punishment is generally death.