Few New Testament passages are as controversial as the warnings against apostasy in the book of Hebrews (2:1–4; 3:7–4:13; 6:4–12; 10:26–39; 12:15–25). These passages pose a challenge to believers. For one, they seem to speak about an unforgivable sin that makes it “impossible” (6:4; cf. 12:17) to repent and be forgiven. They can be read as implying Christians can lose their salvation. They seem to contradict passages that claim a true Christian is preserved by God and perseveres to the end (1 Cor. 1:8; Phil. 1:6; 1 John 5:4–5).
The questions raised by these passages are important and require answers. At worst, a misunderstanding can engender an obsessive or fearful introspection that risks damaging our relationship with our heavenly Father.
On closer examination, particularly of 12:15, we’ll see that Hebrews doesn’t contradict biblical teaching about true believers’ perseverance but warns against the hidden danger of a false profession.
Hear Hebrews with Old Testament Ears
Misunderstanding this passage can engender an obsessive or fearful introspection that risks damaging our relationship with our heavenly Father.
Often, we struggle to understand Scripture’s words because we don’t hear them in context. Hebrews 12:15, the opening verse of the last “warning passage,” is an excellent example. Hearing this verse with Old Testament ears will help clarify the purpose of the warning passages. The text reads, “See to it that no one fails to obtain the grace of God; that no ‘root of bitterness’ springs up and causes trouble, and by it many become defiled.”
The passage goes on to compare this “root of bitterness” to Esau who rejected his birthright and subsequently found “no chance to repent, though he sought it with tears” (vv. 16–17). Like Hebrews 6 (the most famous warning passage), this text warns against falling away and countenances a point of no return. Let’s examine why the hypothetical apostate is described as a “root of bitterness” and how this sheds light on the text.
Root of Bitterness in the Old Testament (Deut. 29:18)
Hebrews 12:15 alludes to the covenant renewal in Deuteronomy, where Moses warns,
Beware lest there be among you a man or woman or clan or tribe whose heart is turning away today from the LORD our God. . . . Beware lest there be among you a root bearing poisonous and bitter fruit, one who, when he hears the words of this sworn covenant, blesses himself in his heart, saying, “I shall be safe, though I walk in the stubbornness of my heart.” . . . The LORD will not be willing to forgive him. (Deut. 29:18–20, emphasis added)
This is perhaps the most explicit Old Testament text that warns about the possibility of unbelievers (“bitter roots”) within the covenant community and connects this with apostasy and the subsequent impossibility of forgiveness. The link between Hebrews 12:15 and the Greek translation of Deuteronomy 29:18 is exceptionally strong, and the author of Hebrews clearly has this earlier passage in mind.
But that author wasn’t the first Scripture reader to draw on Deuteronomy 29:18–19 to highlight the danger of false profession.
Gall of Bitterness (Acts 8:23)
In Acts 8:23, we find a second New Testament allusion to the Deuteronomy passage. After professing faith in Christ, Simon the Magician attempts to buy the power to confer the Holy Spirit to others. Peter explicitly warns him about the genuineness of his profession: “You have neither part nor lot in this matter” (v. 21). Closely echoing the Greek translation of Deuteronomy 29:18, Peter tells Simon that his heart is “in the gall of bitterness” (v. 23).
Deuteronomy 29:18–19 generates the vocabulary for speaking about the danger of false conversion. We often use phrases like “drinking the Kool-Aid” or “crossing the Rubicon” to draw on shared cultural knowledge to make implicit points. If we refer to someone as “Benedict Arnold,” this isn’t just a name but an accusation of betrayal. Similarly, New Testament authors often draw on well-known Old Testament phrases to make points that escape our notice if we miss the references.
Call to Cling to Christ
When the author of Hebrews describes potential apostates as “bitter roots” in the community and compares them to Esau, his point is clear: Some who are outwardly part of the covenant family have hearts that are “not right before God” (Acts 8:21)—“evil unbelieving” hearts (Heb. 3:12) that will eventually manifest in apostasy.
Hebrews’s warnings are real. Those who are unrepentant but think they’re Christians are in danger. If they reject Christ, a state of hard-heartedness will follow.
Those who are unrepentant but think they’re Christians are in danger.
This doesn’t mean repentant “prodigal sons” cannot receive forgiveness but that hardened apostates will, like Esau, “find no room” in their hearts to repent (author’s trans). The warnings of Hebrews call us to examine our hearts and cling to Christ. They aren’t, however, intended to shake the assurance of true believers. There’s no sin a Christian can commit that will revoke God’s decree of election, turn the Father’s heart away from his children, or annul God’s promise to preserve us blameless and pure to the end.
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