Isa 57:5

“This shows them to be those who detest God, having a sick hatred for him and ready to eat blood. There was nothing new in this; it was a long established custom. For you are the ones who have from long ago called on idols under a leafy tree.… Your guilt is that you first think to kill your firstborn and then offer libations to impure demons and soulless idols; so slaying will also be your portion and your lot.… Should I not be angry with these people? Is there not a good cause for my anger?”

“הנחמים באלים The best of the various explanations of this phrase is that it refers to idolatry; הנחמים Who are conceived, similar in form to הנצבים that stood (Gen. 45:1), is the Niphal of יחם to conceive; comp. בכלּ יַחֵם whensoever (the stronger cattle) did conceive (Gen. 30:41). This expression is the description of children of transgression (ver. 4); comp., And in sin did my mother conceive me (Ps. 51:7). שחטי הילדים Slaying the children in honour of the idols; comp. ואשחט and I pressed (Gen. 40:11). They act like a harlot that kills her children. בחלקי Among the smooth stones. Comp. חלוקי אבנים smooth stones (1 Sam. 17:40). Among the smooth stones of the stream is thy portion. They seek for smooth stones to shape them into idols.”

“Second, he accuses them of idolatry. And first, he sets out the custom: are not you wicked children, above: woe to the sinful nation, a wicked people, ungracious children (Isa 1:4); second, he sets out the species of sin: who seek your comfort in idols. And he adds to the weight of their sin of idolatry from three things: first, from the variety of places; second, from the violation of the divine covenant: you have discovered yourself near me (Isa 57:8); third, from their eagerness for sinning: you have loved their bed (Isa 57:8). Now the variety of places in which they sacrificed is shown in three ways: first, as to pleasant places; second, as to lofty places: upon a high and lofty mountain (Isa 57:7); third, as to familiar places: and behind the door (Isa 57:8). Concerning the first, he does four things. First, he describes the pleasantness of the places, either from the shade of trees, who seek your comfort in idols under every green tree: for on every high hill, and under every green tree you didst prostitute yourself (Jer 2:20); or from the abundance of waters: sacrificing children in the torrents, that is, sacrificing your own children: you have taken your sons, and your daughters, whom you have borne to me: and have sacrificed the same to them to be devoured (Ezek 16:20); they shed innocent blood (Ps 105[106]:38).”