John Gill Commentary Ezekiel 16:20

"Moreover thou hast taken thy sons and thy daughters, whom thou hast borne unto me, and these hast thou sacrificed unto them to be devoured. Were thy whoredoms a small matter," — Ezekiel 16:20 (ASV)

Moreover you have taken your sons and your daughters
Their own flesh and blood; which were more than to take their clothes, and cover their idols with them, and their food, and set it before them; to part with them was much, but to part with these, and that in such a shocking manner as after mentioned, was so irrational and unnatural, as well as impious and wicked, as is not to be paralleled; and what increased their wickedness was, that these were not only their own, but the Lord's:

whom you have borne to me ;
for, though they were born of them, they were born to the Lord, the Creator of them, the Father of their spirits, and God of their lives, and who had the sole right to dispose of them; nor was it in the power of their parents to take away their life at pleasure; for the Lord only has the sovereign power of life and death:

and these you have sacrificed to them :
the male images before mentioned; one of which was Molech, who is here particularly designed:

to be devoured ;
in the arms of that image; or to be consumed by fire, in which they were burnt, when sacrificed to it. The Targum is, "for oblation and worship;"

[is this] of your whoredoms a small matter ;
which was so dreadfully heinous and inhuman, yet by some reckoned a small matter; this was not the least of their idolatries, but, of all, the most shocking, and the most aggravated: or the sense is, is it a small thing that you should play the harlot, or worship idols? is it not enough for you to do so, but you must sacrifice your children also to them? and which are not only yours, but mine, as follows: