Bitterness is the worst kind of disability. It affects every aspect of your mind, body and spirit. When held onto long enough it will destroy you. Bitterness is also a choice. You can choose to keep it or let it go. In the end, it will say more about you than anyone else.
In Matthew 5:5-9 it states, "Blessed are the meek for they shall inherit the earth. Blessed are those who hunger and thirst for righteousness, for they shall be satisfied. Blessed are the merciful, for they shall receive mercy. Blessed are the pure in heart, for they shall see God. Blessed are the peacemakers, for they shall be called the sons of God."
The Bible does not say that blessed are the angry, bitter, jealous, and vengeful. Think about that for a moment. Are you hanging onto these emotions? It's okay to feel angry when you have been wronged or hurt, but you need to forgive and let not the sun go down on your anger as the Bible states in Ephesians 4:26. God understands the feelings we have, but he also wants us to put them aside for the sake of peace.
I've found in my life that when someone is bitter towards me, I pray for them to be blessed. This may not be what you feel like doing but, it restores peace in your spirit and gives rest.
There are times when it best just to stay away from bitter people and pray for them from a distance. God is the only one who can soften their hearts, and nothing you can say or do will change them.
It also helps to forgive one another, for Christ died so our sins may be forgiven, and it is out of respect for our Lord that we do this. Forgiveness is an incredible gift for ourselves, by the way. Take advantage of it and heal your own heart.
One final thought I have on fighting bitterness is to chose mercy. Mercy is a beautiful word and aids in the ability to forgive. Remember, bitterness is a choice. Guard your own heart, for everything you do flows from it. Proverbs 4:23.
