Ephesians 4:31 (NKJV)
31 Let all bitterness, wrath, anger, clamor, and evil speaking be put away from you, with all malice.
Hebrews 12:15 (NKJV)
15 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;
