Sometimes forgiving someone is hard. People tend to hurt us more than once. When someone hurts you and you forgive them, everything seems okay. But then they turn around and hurt you again, it is harder to forgive them.
Jesus says we must forgive them. He says to forgive even if the other person wrongs us seventy times seven. (It doesn't mean you don't need to forgive them again after 490 times). It means we are to always forgive their wrongs.
God knows that forgiveness is important. Look at Him, He forgives us every time we ask Him (as long as we are sincerely sorry). To forgive others pleases God because then He may forgive us and also He will forgive them.
It also relieves our bitterness we harbor in ourselves and toward the other person. When we forgive that person (or persons) who did wrong to us, it takes a heaviness--a terrible burden of bitterness out of us; plus it takes away the pain we hold within ourselves. Forgiveness also releases the power that we give that person to destroy our life. Satan loves to see us in bondage of unforgiveness. Don't give him that power over you.
Forgiveness is necessary so that we may become a better person instead of bitter person. Just remember how Jesus died for us so that we may be forgiven. How can we not forgive others?
Luke 17:3,4(Amplified Bible)
John 20:23 (Amplified Bible)
Ephesians 4:31,31 (Amplified Bible)
Colossians 3:13 (Amplified Bible)