Matthew 18:21-35 (KJV)
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.
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.

Forgiveness is essential to keep the unity.
The LORD told us in John 13:34-35 (KJV) “A new commandment I give unto you, That ye love one another; as I have loved you, that ye also love one another. [35] By this shall all men know that ye are my disciples, if ye have love one to another.”
Love is the hallmark of Christians. Loves is required to be able to forgive anyone especially those who are ones enemies. “Matthew 5:43-45 (KJV) Ye have heard that it hath been said, Thou shalt love thy neighbour, and hate thine enemy. [44] But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you; [45] That ye may be the children of your Father which is in heaven: for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust.”.
On the other hand unforgiveness rob us of unity. “1 Corinthians 1:10 (KJV) Now I beseech you, brethren, by the name of our Lord Jesus Christ, that ye all speak the same thing, and that there be no divisions among you; but that ye be perfectly joined together in the same mind and in the same judgment.”.

Therefore let us be encouraged to express the love of GOD He has given us. “1 Peter 4:8 (KJV) And above all things have fervent charity among yourselves: for charity shall cover the multitude of sins.”.
As a church, when we practice this, we foster a save environments where people can make mistakes and grow without the fear of judgement and condemnation. An environment where everyone knows they are accepted with all our faults. An environment where we want to grow and be transformed to be come more like Jesus Christ. On top of that the LORD commands a blessing when we are together in unity. “Psalms 133:1-3 (KJV) A Song of degrees of David. Behold, how good and how pleasant it is for brethren to dwell together in unity! [2] It is like the precious ointment upon the head, that ran down upon the beard, even Aaron’s beard: that went down to the skirts of his garments; [3] As the dew of Hermon, and as the dew that descended upon the mountains of Zion: for there the LORD commanded the blessing, even life for evermore.”