The prophet’s accusations in this verse indicate some of the Israelites practiced Canaanite forms of worship.

Who burn with lust among the oaks, under every green tree: The rhetorical question begun in the last two lines of verse 4 continues to the end of this verse, but it is possible to start a new question here by saying “Are you not the people who…?” Burn with lust renders a Hebrew verb that usually means “to be warm” (see, for example, 44.15-16). However, in this context it means “to be anxious to have sex.” A comparable English slang expression is “to be hot.” Many English versions use a phrase with the term “lust,” but New Jewish Publication Society’s Tanakh leaves room for a wider interpretation with “inflame yourselves.” It adds a footnote to explain that this happens “in some frenzied idolatrous rite.”

The Hebrew word for oaks is ʾelim. ʾEl is the general Semitic word for “god,” so ʾelim may be an unusual plural form of ʿel that can mean “gods.” We follow this sense in the third example below, but no version consulted adopts it. Most versions say oaks (RSV/NRSV, New International Version) or “terebinths” (New Jerusalem Bible, New American Bible, New Jewish Publication Society’s Tanakh). Revised English Bible has “sacred oaks” to indicate that these trees were associated with Canaanite worship (see the comments on 1.29; see also Jdg 9.37; Hos 4.13). Among the oaks is expanded by the phrase under every green tree, which is a hyperbole to emphasize the wide extent of the Canaanite worship practices. This phrase is a favorite one of Jeremiah (see Jer 2.20; 3.6, 13). Every green tree refers to all the healthy trees full of leaves. This phrase may be rendered “every lush tree” or “every leafy tree.”

Good News Translation gives the plain sense of the first two lines of this verse by saying “You worship the fertility gods by having sex under those sacred trees of yours.” The people worshiped the fertility gods in this way to have more children and plentiful livestock and crops. Although Good News Translation‘s rendering is quite free and explicit, it is a possible model for translators who would find a more formal translation meaningless.

Who slay your children in the valleys, under the clefts of the rocks: The prophet also accuses the people of sacrificing their children. Human sacrifices in Canaan were offered to the gods Molech (see verse 9) or Baal. There is some evidence that this Canaanite practice found its way into Israelite religion, but King Josiah tried to put a stop to it (see 2 Kgs 23.10). However, it probably survived and was still practiced after the exile. Apparently, this religious ritual was performed when there was a serious crisis in the land. It is not clear why it was done in the valleys. The word rendered valleys refers to a wadi, which is normally a dry riverbed in which water runs only after heavy seasonal rain. It is also unclear why the human sacrifices took place under the clefts of the rocks. For the clefts of the rock, see the comments on 2.21. New International Version renders this whole phrase as “under the overhanging crags.” Good News Translation provides a good model with “in the rocky caves.”

Translators may break the long rhetorical question here into several shorter questions (see the first example below) or strong statements (see the second and third examples below). For the translation of this verse consider the following examples:

• Are you not those who have ritual sex
among the oak trees and under every lush tree?
Are you not those who offer your children as sacrifices in the wadis?
Do you not offer them also in the holes of the rocks [or, mountains]?

• You are people who have ritual sex
under the oak trees and every [other] leafy tree!
You offer your children as sacrifices
in the wadis and in the rocky caves!

• You have sex with the gods under every leafy tree!
You kill your children as sacrifices
in the valleys and in the cracks in the rocks!

Quoted with permission from Ogden, Graham S. and Sterk, Jan. A Handbook on Isaiah. (UBS Helps for Translators). New York: UBS, 2011. For this and other handbooks for translators see here .