Leviticus 20:2

And with the sons of Israel speak thou, to say: A man of the family of the sons of Israel, whether young or old, who shall make (an offering) of his offspring unto Molek to be burned in the fire, shall be verily put to death: the people of the house of Israel shall punish his guilt by the infliction of stones;

The people of the land The land where he dwells, whether as a native or as a foreigner. This punishment is imposed only if the crime was perpetrated in public.

אשר יתן מזרעו למולך, after the Torah had explained G’d’s plan to sanctify the Israelites in order for them to become as much like Him as is possible for any creature, and He taught them the path to take to achieve such an aim, it now warns of a lifestyle which could produce the opposite result.
The Torah now discusses the penalties that would befall three specific categories of people who defy the Torah and take a different path toward what they perceive to be their success in life on this planet. People guilty of these practices would contaminate their souls beyond redemption.
Category one are people who follow mistaken philosophies, a prime example being people who follow the cult of the Moloch. In verse 3 the Torah spelled out the spiritually negative consequences of following this cult with the words למען טמא את מקדשי, “this would counteract My declared purpose of sanctifying (you)”.
Category two, the relying on such oracles as ov and yidoni have already been described as spiritually contaminating in 19,31 with the words אל תבקשו לטמאה בהם, “do not attempt to become spiritually contaminated by them.” In 18,24-25 the Torah had already drawn attention to the fate which befalls the [previous inhabitants of the land of Canaan being due to their relying on such oracles.
The third category of spiritually counterproductive practices is the ingesting of the kind of food that the Torah outlawed in Leviticus chapter 11 and the negative results of violating these laws are repeated again in verse 25 of our chapter והבדלתם...ולא תשקצו את נפשותיכם לטמא וגו', “separate yourselves…do not become detestable…to spiritually contaminate yourselves.”
In Parshat Emor the Torah speaks of a different kind of spiritual (ritual) contamination which is caused mostly passively through contact directly or indirectly with dead human bodies. It also discusses physical blemishes, especially of priests, which disqualify such people from carrying out their duties in the holy precincts of the Temple. However, the legislation in that portion concentrates on the impediment such kind of ritual (spiritual) contamination represents when the afflicted party handles sacred matters, sacrificial flesh, etc., in any shape or form. Other aspects are the abuse of such sacred objects which as well as incestuous marriages, i.e. contaminating the pure semen a person has been born with by incestuous sexual relations with forbidden partners.
Here the Torah begins with the desecrating of one’s semen by sacrificing it to the abominable Moloch cult. The penalty to be applied to people guilty of this sin, which is perpetrated in public, is עם הארץ ירגמוהו באבן, the people at large are to stone the father to death. Only by the expression of jealousy on behalf of G’d can such a sin be wiped out, seeing it had a potentially spiritually negative effect on the entire nation. Naturally, the penalty by the hand of man is applied only if there was testimony by valid witnesses to the deed and the perpetrator had first been cautioned of the penalty to expect if he would go through with his intention.