If you forgive not men their trespasses, neither will your heavenly Father forgive your trespasses.
Matthew 6:15. Jesus said further, when you come to God to offer your gift, and remember that your brother has something against you, (not that you have something against your brother), leave your gift before the altar, first be reconciled to your brother, then come and offer your gift.
This is more than saying, “I’m sorry”. This takes getting to the bottom of your brother’s feelings of anger and hurt. It takes talking with him to learn the basis for his anger and hurt. What did you do or say that contributed to or caused his reaction? Angry feelings are often a reaction to perceived injustice, and if that perceived injustice is against one’s self, and both parties don’t take time to talk about their feelings and reactions, those feelings and reactions don’t go away. This is why someone may have something against you, because you were the one who did or said something that raised up these angry feelings in the other person. This may occur without you even realizing that it happened. Your love for your brother would prompt you to help him get rid of his angry feelings.
So love wishes no ill will to another.
Love wishes only good for others, and considers the good toward another above that toward one’s self. Since it is the Holy Spirit that would lead one to remember that someone has something against you, by not acting on these thoughts one would be ignoring the Holy Spirit. How, therefore, would the gift being presented be acceptable to God?
Read again 1 Corinthians 13.