Leviticus 18:21 Midrash: Devarim Rabbah, Sifra & Sifrei Devarim

3) who gives of his seed to the Molech": and not to other varieties (of idolatry). "who gives of his seed to the Molech": What is the intent of this? (i.e., Is it not already written (Vayikra 18:21) "And from your seed you shall not give, etc."?) (For) if from there, I might think that even if he (himself) passed (him through fire) and did not give him (to the priest of Molech to do so), he would be liable; it is, therefore, written (for emphasis) "who gives of his seed." I might think that even if he gave, but did not pass, he is still liable; it is, therefore, written (Vayikra 18:21) "And from your seed you shall not give to pass to the Molech." I might think he would be liable even if he did not pass him through fire; it is, therefore, written (Devarim 18:10) "There shall not be found among you one who passes his son or daughter through fire" "passing"-"passing" for an identity (gezeirah shavah) — Just as "passing" here is for the Molech, so "passing" there; and just as "passing" there is through fire, so, "passing" here. In sum: There must be giving, and passing, through fire, to the Molech.

R. Chanina b. Antignos says: Come and see the rationale of the language of Scripture. Why is it called "Molech" (viz. Vayikra 18:21)? To designate anything that they made to rule (yamlichuhu") over them — even a splinter, even a pebble.