Isaiah 57:5 Commentary: Inflamed with Idols, Slaying Children

This verse sits in a series of indictments in Isaiah 56, 57 against unfaithful leaders and people. The opening verses (57:1-2) describe the righteous being taken away from coming evil, setting a stark contrast with the wicked now addressed. The people are called “sons of a sorceress, offspring of adulterers and prostitutes” (v. 3), establishing the language of covenant betrayal as marital unfaithfulness.

Cultic tree worship was widespread in Canaanite religion, where groves of terebinths and oaks were considered sacred sites for the goddess Asherah. Deuteronomy 12:2 commands Israel to destroy all such places “on the high mountains, on the hills, and under every green tree.” The repetition of “under every green tree” in this verse is a direct echo of that prohibition, showing that the people have returned to the very practices they were told to eradicate.

The “slaying of children in the valleys” alludes specifically to the worship of Molech in the Valley of Hinnom (Tophet), a practice documented from the reigns of Ahaz and Manasseh (2 Chronicles 28:3; 33:6). The “clefts of the rocks” likely refer to natural caves or crevices associated with mystery cults and underworld deities. Keil & Delitzsch view the prophet as writing from a perspective after the captivity, using colors from Manasseh's reign to address post-exilic syncretism. The Cambridge Bible suggests a possible reference to Samaritan communities. Either way, the verse depicts a people deeply enmeshed in the religious practices of surrounding nations.

The consulted sources note no significant textual variants for this verse. The main interpretive issue is lexical: the Hebrew באלים (ba'ēlı̂ym) may be read either as “among the oaks” (from איל 'el, terebinth) or “with idols” (from אל 'el, god). The Septuagint and Vulgate adopt the latter, while most English versions follow the former. This difference affects the imagery but not the overall condemnation of idolatry.

Early Christian interpreters, including Jerome, read this verse within Isaiah's larger indictment of covenant unfaithfulness, often allegorizing the “oaks” as the pride of the world and the “children” as the spiritual offspring devoured by false teaching. Medieval commentators continued this moral interpretation. During the Reformation, Protestant exegetes like John Calvin and John Gill applied the text to the practices of the Roman Catholic Church, seeing parallels in the veneration of saints and sacred objects, Gill explicitly compares the “oaks” to images made of wood worshipped in the Papacy. Modern scholarship, informed by archaeology, reads the verse against the background of Canaanite religion, emphasizing the literal cultic dimensions. Across traditions, the verse has served as a stark warning against the seduction of syncretism and the horrifying cost of abandoning the living God.

Three-point outline

1. The Object of Our Devotion, The people “inflame themselves among the oaks.” The tree represents a created object elevated to divine status. We too burn with passion for things that promise life but demand everything in return.
2. The Cost of False Worship, “Slaying the children in the valleys.” Idolatry never stays private; it consumes what is most precious. When we give our hearts to anything other than God, it eventually devours the innocent and the vulnerable.
3. The God Who Confronts, The verse is part of God's courtroom indictment. He sees, He names, and He will not be placated by ritual. The hope of the chapter (v. 15) is that He dwells with the contrite, not those who hide in caves.

Five-point outline

1. Place, “Among the oaks, under every green tree.” Geography matters. Where do we go to find meaning?
2. Passion, “Who inflame yourselves.” The Hebrew word implies heat, intensity, arousal. Our desires shape our worship.
3. Violence, “Slaying the children.” Sin escalates. What starts as a thrill ends as a sacrifice of life.
4. Secrecy, “Under the clefts of the rocks.” Hidden places. We often practice our idolatry where we think no one sees.
5. Indictment, The verse is explicit, graphic, and public. God's judgment begins with exposure. But exposure is also the first step toward healing.

Illustration hooks

• A person scrolling through their phone at 1 a.m., seeking comfort or escape, that “green tree” of digital distraction.
• A worker sacrificing family time, health, and even conscience for a promotion, the modern valley of Molech.
• A culture that excuses the destruction of the unborn or the vulnerable in the name of personal freedom, the children slain under the rocks of ideology.

Questions your congregation is asking

• “Does God really care what I do in private as long as I don't hurt anyone?”
• “How can we identify the ‘green trees’ in our own lives?”
• “If God is so against idolatry, why does He seem silent about it for so long?” (see v. 11)

This verse pulls back the curtain on what happens when God's people abandon Him for other gods. It is raw, shocking, and meant to provoke self-examination. As you discuss, remember that the same God who exposes sin also offers refuge (Isaiah 57:15). Let the honesty of the passage lead to honest conversation.

Discussion questions

1. What does the description “inflaming yourselves among the oaks” suggest about the emotional energy of idolatry?
2. The verse mentions “under every green tree” and “under the clefts of the rocks.” Why do you think idolatrous worship sought specific places? What does that say about human nature?
3. Child sacrifice shocks us. How does the Bible use this extreme example to show us the logical endpoint of any idolatry?
4. In the surrounding verses (57:3-13), God uses the language of prostitution and adultery. How does that metaphor connect to the literal practices described in verse 5?
5. What are some “green trees” in our society, things that promise life but demand sacrifice?
6. How does the surrounding context (the righteous perish in vv. 1-2) frame the seriousness of this sin?
7. If someone in your group said, “I have never sacrificed a child, but I see how my ambitions harm my family,” how would you respond with grace and honesty?