Hebrews 12:15, in the King James Version, refers to a “root of bitterness” which, if it springs up, will “trouble you, and thereby many be defiled.” What exactly is this “root,” and how can it defile many? True to the purpose of the book of Hebrews, we can find some explanations in the Old Testament, which are confirmed by other uses in the New Testament.
First, it is helpful to look at a more recent translation of the entire verse. The New International Version reads, “See to it that no one misses the grace of God and that no bitter root grows up to cause trouble and defile many” (Hebrews 12:15). This passage is directed at the whole church.
In the Hebrew culture, any poisonous plant was called a “bitter” plant. Poison destroys, and the result of ingesting a poisonous plant would be bitter, indeed. The author of the book of Hebrews uses a “bitter root” as a metaphor for that which would bring harm to the church.
There is a verse in the Pentateuch that closely mirrors the wording in Hebrews. In Deuteronomy 29, Moses reviews the covenant between God and Israel. In this context, he says, “Make sure there is no root among you that produces such bitter poison” (Deuteronomy 29:18). This particular “bitter poison” is idolatry in defiance of the covenant. Throughout the Old Testament, the Hebrew word translated “bitter poison” refers either to the unfaithful (Deuteronomy 29:18; Amos 6:12) or to their punishment (Jeremiah 8:14; 9:15; 23:15).
Moving to the New Testament, we have another reference to the destructive power of bitterness. While rebuking Simon the Sorcerer, Peter tells him to repent of his wickedness, with an added insight: “I see that you are full of bitterness and captive to sin” (Acts 8:23). Simon’s wickedness was his desire to buy the power of the Holy Spirit, essentially treating God as a commodity to enhance his own career as a magician.
So, the “bitter root” in Hebrews refers to a source of evil or wickedness within the church. A root may be small and slow in its growth, but, if it carries poison, it is malignant; it is dangerous. Sin in the church must be diligently rooted out; the result of tolerating wickedness is that “many” will be defiled.
For an example of how God dealt with a “root of bitterness” in the early church, see the story of Ananias and Sapphira in Acts 5. Obviously, God considers pulling up such “bitter roots” to be critically important to the health of His church.