Hebrews 12:15
ESV
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;
NIV
See to it that no one falls short of the grace of God and that no bitter root grows up to cause trouble and defile many.
NASB
See to it that no one comes short of the grace of God; that no root of bitterness springing up causes trouble, and by it many become defiled;
CSB
Make sure that no one falls short of the grace of God and that no root of bitterness springs up, causing trouble and defiling many.
NLT
Look after each other so that none of you fails to receive the grace of God. Watch out that no poisonous root of bitterness grows up to trouble you, corrupting many.
KJV
Looking diligently lest any man fail of the grace of God; lest any root of bitterness springing up trouble you, and thereby many be defiled;
NKJV
looking carefully lest anyone fall short of the grace of God; lest any root of bitterness springing up cause trouble, and by this many become defiled;
What does Hebrews 12:15 mean?
This verse continues to give practical steps Christians ought to take in response to persecution and hardship. Earlier, the writer encouraged believers to "hold fast" (Hebrews 3:6; 10:23) in the face of struggles. Most of the suffering we endure as Christians is not as heavy as it could be (Hebrews 12:4). And, God intends those experiences for our good—to "train" us into a more mature faith (Hebrews 12:11). While we grow individually, we also need to be careful of how we interact with other believers. The prior verse mentioned the need to live in peace, as well as the importance of pursuing holiness.The reference to those who "[fail] to obtain the grace of God" could mean those who are false believers. That would harmonize with other New Testament warnings about those who claim to be godly, but are not (Matthew 7:15, Jude 1:12). Upcoming verses tie into the example of Esau, who was careless towards his own birthright, also seen as a sign of one without real faith in God. While that's possible, the context seems mostly to focus on something else: a command regarding those within the church who are defiant towards God and His holiness.
Prior verses mentioned the importance of holiness (Hebrews 12:14), and other New Testament verses mention the importance of not tolerating brazen sin among those who claim the name of Christ (1 Corinthians 5:11). Earlier, a warning in this same letter was given to those who believe, but who fail to obey and are judged accordingly (Hebrews 10:26–31). The "root of bitterness" mentioned here re-establishes a metaphor used in Deuteronomy 29:18–19. There, the people of Israel were warned about those who assumed they'd be blessed and protected by God, despite their willful rebellion.
It seems, then, that the writer's point is about those who are disobedient towards God. Old Testament Hebrew uses the word "bitter" as a reference to poison. Here, the "bitter roots" are said to cause trouble and defilement. Whether those persons are outright false Christians, or merely rebellious believers, their influence is the same. They cause controversy and lead others into sin. Such persons cannot be allowed to remain in the body of believers (1 Corinthians 5:13).
The following verse will continue addressing the need for vigilance against certain spiritual errors, using the infamous example of Esau.
