Some verses to assist you in understanding that forgiveness is essential as a Christian. Though it is hard, if we do not forgive others, then God will not forgive us.
Mat 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?
Mat 18:22 Jesus saith unto him, I say not unto thee, Until seven times: but, Until seventy times seven.
Luk 17:4 And if he trespass against thee seven times in a day, and seven times in a day turn again to thee, saying, I repent; thou shalt forgive him.
Mat 18:35 So likewise shall my heavenly Father do also unto you, if ye from your hearts forgive not every one his brother their trespasses.
Mar 11:25 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.
Mar 11:26 But if ye do not forgive, neither will your Father which is in heaven forgive your trespasses.
And remember the prayer that Jesus taught us
Mat 6:9 After this manner therefore pray ye: Our Father which art in heaven, Hallowed be thy name.
Mat 6:10 Thy kingdom come. Thy will be done in earth, as [it is] in heaven.
Mat 6:11 Give us this day our daily bread.
Mat 6:12 And forgive us our debts, as we forgive our debtors.
Mat 6:13 And lead us not into temptation, but deliver us from evil: For thine is the kingdom, and the power, and the glory, for ever. Amen.
Mat 6:14 For if ye forgive men their trespasses, your heavenly Father will also forgive you:
Mat 6:15 But if ye forgive not men their trespasses, neither will your Father forgive your trespasses.
God bless you!