Bitterness is that state of mind that willfully holds on to angry feelings, ready to take offense, able to break out in anger at any moment.
Bitterness is resentful cynicism that results in an intense antagonism or hostility toward others. The Bible teaches us to “get rid of all bitterness, rage and anger, brawling and slander, along with every form of malice.” It then goes on to tell us how to deal with such bitterness and its fruits by being “kind and compassionate to one another, forgiving each other, just as in Christ God forgave you” (Ephesians 4:31-32).

The person who is bitter is often resentful, cynical, harsh, cold, relentless, and unpleasant to be around. Any expression of these characteristics is sin against God; they are of the flesh, not of His Spirit (Galatians 5:19-21). Hebrews 12:15 warns us to “see to it that no one misses the grace of God and that no bitter root grows up to cause trouble and defile many.” We must always be wary of allowing “bitter roots” to grow in our hearts; such roots will cause us to fall short of the grace of God. God wills that His people live in love, joy, peace, and holiness—not in bitterness. Therefore, the believer must always watch diligently, being on guard against the dangers of bitterness.

God will help you ONLY if you ask for his help.