The writer to the Hebrews wrote this:
Pursue…holiness—without it no one will see the Lord.
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. (Hebrews 12:14-15)
A lot of people, when they see the phrase “root of bitterness,” think that God is warning against holding bitterness in your heart.
Of course, we shouldn’t hold bitterness in our hearts, but actually, the author of Hebrews is referring to Moses’ words in Deuteronomy 29, where he said,
Be sure there is no man, woman, clan, or tribe among you today whose heart turns away from the Lord our God to go and worship the gods of those nations.
Be sure there is no root among you bearing poisonous and bitter fruit.
When someone hears the words of this oath, he may consider himself exempt, thinking, ‘I will have peace even though I follow my own stubborn heart.’
This will lead to the destruction of the well-watered land as well as the dry land. (Deuteronomy 29:18-19)
According to Moses, what is a root bearing poisonous or bitter fruit?
It’s a heart that instead of fearing God, willfully turns away from him and goes its own way.
Moses warned the Israelites against people like that, saying that such an attitude could spread among the Israelites and destroy them.
The writer of Hebrews takes Moses’ words and warns the church against the same attitude.
That attitude can show itself in many ways, but particularly in idolatry, which is Moses’ primary concern.
Idolatry is not just worshiping other gods, but putting anything in front of God, whether it’s money, things, pleasure, or whatever else it may be.
Anything you put before God is your idol.
But as God’s people, we now serve him. We cannot say, “I’ll just live as I want to, serving other idols.”
God has not taught us everything he knows, but what he has taught us, we are accountable for (Deuteronomy 29:29).
And an attitude of willful rebellion will cause you to fall short of the grace of God in your life.
The grace of God gives us a heart of thanksgiving and a desire to please him.
If you don’t have that kind of heart, you don’t really know God’s grace at all.
Moment to Moment (Bible blog) 
2 replies on “A bitter root”
actually I don’t think that is correct. The original in deut points to the people deciding that God is not providing the blessings that they are expecting or desiring and so rather than trust him they turn to idols which are more easily manipulated. It is a disillusionment with living by faith.
Thanks for your feedback. Looking at the passage again, I don’t know that I totally agree with your interpretation.
I don’t see anything in the passage that says they were wavering because they decided God was not providing the blessings they were expecting.
That said, I can’t say I particularly feel comfortable with my own interpretation that I held at the time. I was probably reading into the passage too much in coming up with, “I’m saved so I’ll live as I want to.” Something may have been happening in the time that made my mind go in that direction, but if there was, I don’t remember it.
I made some changes to the post, and you may or may not agree with what I wrote, but I do think it’s closer to what Moses meant.
Thanks again, and God bless.