Hebrews 12:15 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 be defiled;

Ephesians 4:31-32 Let all bitterness and wrath and anger and clamor and slander be put away from you, along with all malice. Be kind to one another, tender-hearted, forgiving each other, just as God in Christ also has forgiven you.

Philippians 4:11-13 Not that I speak from want, for I have learned to be content in whatever circumstances I am. I know how to get along with humble means, and I also know how to live in prosperity; in any and every circumstance I have learned the secret of being filled and going hungry, both of having abundance and suffering need. I can do all things through Him who strengthens me.

Bitterness: What is it? How to Overcome It – Pastor Patrick Hines Reformed Christian Podcast