Luke 23:34: Then said Jesus, Father forgive them; for they know not what they do. And they parted his raiment, and cast lots.
Jesus is the greatest forgiver there ever was. If it wasn't for his forgiveness of our sins, we would never be able to go to heaven because God cannot let sin into heaven. Since Jesus has forgiven us, we should forgive one another.
Ephesians 4:32: And be ye kind one to another, tenderhearted, forgiving one another, even as God for Christ's sake hath forgiven you.
Some might say, but you don't know what they did to me. I was mistreated and I don't deserve that. Was there ever anyone who was as mistreated as Jesus was, and yet he forgave. He didn't deserve to be beaten and have his beard pulled out and have a crown of thorns placed on his head, and he didn't deserve to be nailed to the cross. Being unforgiving is not being like Jesus.
The bible also teaches that if we do not forgive one another, then God will not forgive us. In Matthew chapter 6 is the Lord's prayer, and it talks about forgiving.
Matthew 6:12: And forgive us our debts, as we forgive our debtors.
Matthew 6:14: For if ye forgive men their trespasses, your heavenly Father will also forgive you.
15: But if ye forgive not men their trespasses, neither will your Father forgive your trespasses.
So these verses make it very clear that if we do not forgive others God will not forgive us. I certainly want God to forgive my sins, so I must forgive others, and if you want to be forgiven of your sins, you must forgive others too. The bible is crystal clear on this: you don't forgive others, God will not forgive you. There is plenty of sin in all of us to need God's forgiveness.
Another reason to forgive others is so God will hear our prayers.
Mark 11:24: Therefore I say unto you, What things soever ye desire, when ye pray, believe that ye receive them, and ye shall have them.
25: And when ye stand praying, forgive, if ye have ought against any: that your Father also which is in heaven may forgive you your trespasses.
26: But if ye do not forgive, neither will your Father which is in heaven forgive your trespasses.
So if we go to pray and have unforgiveness in our heart towards anyone, God will not hear our prayer. He will only listen to the prayers of someone who totally forgives other people. I don't know about you, but I want God to hear my prayers and answer them. Unforgiveness is like a road block that blocks our prayers from God.
Someone may say, but I've already forgiven him hundreds of time and he keeps doing the same thing, I cannot forgive anymore. But the bible says we should always forgive, no matter how many times it is.
Matthew 18:21: Then came Peter to him, and said, Lord, how oft shall my brother sin against me, and I forgive him? till seven times?
22: Jesus saith unto him, I say not unto thee, Until seven times: but, Until seventy times seven.
Matthew 18:23: Therefore is the kingdom of heaven likened unto a certain king, which would take account of his servants.
24: And when he had begun to reckon, one was brought unto him, which owed him ten thousand talents.
25: But forasmuch as he had not to pay, his lord commanded him to be sold, and his wife, and children, and all that he had, and payment to be made.
26: The servant therefore fell down, and worshipped him, saying, Lord, have patience with me, and I will pay thee all.
27: Then the lord of that servant was moved with compassion, and loosed him, and forgave him the debt.
28: But the same servant went out, and found one of his fellowservants, which owed him an hundred pence: and he laid hands on him, and took him by the throat, saying, Pay me that thou owest.
29: And his fellowservant fell down at his feet, and besought him, saying, Have patience with me, and I will pay thee all.
30: And he would not: but went and cast him into prison, till he should pay the debt.
31: So when his fellowservants saw what was done, they were very sorry, and came and told unto their lord all that was done.
32: Then his lord, after that he had called him, said unto him, O thou wicked servant, I forgave thee all that debt, because thou desiredst me:
33: Shouldest not thou also have had compassion on thy fellowservant, even as I had pity on thee:
34: And his lord was wroth, and delivered him to the tormentors, till he should pay all that was due unto him.
35: So likewise shall my heavenly Father do also unto you, if ye from your hearts forgive not every one his brother their trespasses.
What the bible is teaching us in this passage is that since God has forgiven us so much and has forgiven us such a huge debt, it would be wrong and very wicked not to forgive our brother or sister for any kind of wrong they may have done us, which is very very small in comparison to what God has forgiven us of.
So in conclusion, it is very important that we forgive others so God will forgive us and also so he will hear our prayers. It is also very wicked to not forgive others since God has forgiven us so much. Most importantly, is that we forgive people because forgiving is to be like Jesus and Christians should always strive to be like Jesus, our saviour and our great example.