Hebrews 12:15 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;
Bitterness – The unresolved violation of your justice system that produces hurt or anger OR prolonged unforgiveness.
FORGIVENESS: a choice of the will to reconcile with an offender by erasing the debt they owe you and living with the consequences.
Ephesians 4:31-32 Let all bitterness, and wrath, and anger, and clamour, and evil speaking, be put away from you, with all malice: Allow these things to be divorced from you
32 And be ye kind one to another, tenderhearted, forgiving one another, even as God for Christ’s sake hath forgiven you.