The one and only message of God
Everyone that has called on the name of the lord for salvation is commanded to be kind to one another. Forgive one another that is how kindness is to be show.
Forgiveness is not probation, i.e., merely suspending the sentence under supervision and specific conditions. Forgiveness is not a reprieve, i.e., temporarily postponing the punishment. Forgiveness results in complete reconciliation and restored fellowship. 
4.32- Be ye kind. Paul summarized Christian character. Keep on becoming kind towards one another—well disposed, useful, benevolent, gracious and gentle mannered, as opposed to being harsh, hard, bitter, and sharp. The person who is kind is full of benign courtesy, is distinguished by gracious deeds, and is desirous of promoting common interests and conferring reciprocal obligations. This kindness is the outward expression of love in the heart and applies to all contacts and situations. Tenderhearted. Merciful, compassionate, pitiful. There is a willingness to be understanding of and patient with the faults and failures of others, ready to put kindness into action.
Forgiving one another. The word “forgive” (Gr charizomai) is built on the same root as the word “grace” and means to bestow favor unconditionally. This means that a Christian will always treat the offending party graciously, letting the wrong go without any claim for punishment or reparation. It means pardoning the guilty person instead of displaying resentment or exercising retaliation.
Forgiveness is not probation, i.e., merely suspending the sentence under supervision and specific conditions.
God’s forgiveness is free, full, and final. When God forgives, He forgets; so must we.
in Christ God is kind (Eph. 2:7), compassionate (Mark 1:41), and gracious (Rom. 8:32) to believers.
What keeps us from giving forgiveness?
“Bitterness” is an irritable state of mind which produces harsh and hard opinions of others. 
A great many people are speaking out of bitterness, and when they do, it hurts. This grieves the Holy Spirit.
Bitterness refers to a settled hostility that poisons the whole inner man. Somebody does something we do not like, so we harbor ill will against him. “Husbands, love your wives and be not bitter against them” (Col. 3:19). Bitterness leads to wrath, which is the explosion on the outside of the feelings on the inside.
Look back to vs.27
Don’t give place for the devil.
Giving place to the devil (v. 27) involves both lying and anger; for Satan is a liar and a murderer. Do we realize that lies and hypocrisy and anger give Satan a foothold in our lives? Cain’s lies and anger led to murder (Gen. 4).
A woman tried to defend her bad temper by saying, “I explode and then it’s all over with.” 
Why should we avoid bitterness?
1. It grieves the holy spirit – 4.30-31
Bitterness in the heart makes us treat others the way Satan treats them, when we should treat others the way God has treated us. 
Example: when your kids are fighting each other how does this make you feel as a parent? Grieved.
Example : man wanted to remarry his first wife. But there was a Problem bitterness towards one another and they divorced each other many year years ago. He said to the pastor, we forgave each other and want to get back together and enjoy each other before we die.
2. Bitterness keeps us from our joy.
a. Have you ever wonder if joy would ever come back in your life?
b. This should be your first sign that you have some bitterness in your heart. Its time to get set free from this bitterness.