We are called to forgive because Jesus forgave us and died for our sins. In the scriptures it is very clear that forgiveness on our part is essential to being forgiven. The Holy Spirit instructed me during one of my first conferences for women who had been sexually abused, to help the ladies to separate the evil spirit behind the action from the person who was made in the image of God. You literally see yourself taking the evil spirit out of the person who hurt you. Then you look at the spirit (of course this is using your imagination or what I believe is the spirit mind) and tell it you are glad that it is eternally damned and you trust that God will see that His enemies (demonic spirits) will forever suffer for the things they provoke or entice people to do. Then you look at the person that yielded to the demonic influence and you ask the Lord to help you see them separate from what the enemy has done to them and through them. You will realize that every human is made in the image of God to reveal something of His character. Satan has attacked human kind to destroy the image of God from being seen on the earth. Now look at that person and realize whatever sin they yielded themselves to practice, Jesus Christ died on the cross and took their punishment for them. The Bible says He tasted death and the grave for us. 

Now forgive them by the grace available through the Holy Spirit. Give them to the Lord and if they are still alive ask the Holy Spirit to draw them to the Lord.

Some people struggle at the moment of forgiveness if the offense was so deep rooted and resulted in bitterness (which is always traced back to blaming God for allowing the offense). Many times I have been led to actually cast out a demon of hate and murder. This spirit usually manifest in anger and threats but as a born again believer we just plead the blood of Christ and command the spirit out in the name of Jesus. You can tell when the person has been set free by the peace that floods their soul. The spirit of hate and murder usually has many other spirits and lies entangled with it. The process to complete freedom is something only the Holy Spirit can orchestrate and we need to yield and continue to grow in understanding truth. God is faithful who will make a way of escape.

The guilt issue opens the door for self hate and condemnation. You will need to examine the lies that you believe about yourself and the situation. One by one bring truth from God’s Word to the lie (stronghold). I have helped people forgive themselves when a sin was committed.
(Scripture references Matthew 6:12-15, Romans 6:6-23, Acts 19:15, Matthew 10:8)