The Father can’t forgive our sins if we don’t forgive other people, and we reap what we sow (see Matthew 6:14-15; Galatians 6:7-8). Sow mercy, and you’ll reap mercy; sow judgment, and you’ll reap judgment. You need to forgive, by the grace of God in your life, to leave the door of your heart open to the Lord.
Unforgiveness gives the devil a foothold, which he needs to create a stronghold. When he has a stronghold, he can block the influence of the Holy Spirit. When you forgive, it keeps the enemy from getting an advantage over you and keeps your fellowship with God flowing freely.
You can have victory over the enemy through the power of the Holy Spirit as you choose to obey God’s Word. So do yourself a favor, and be quick to forgive.