"So if you are presenting a sacrifice at the altar in the Temple and you suddenly remember that someone has something against you, leave your sacrifice there at the altar. Go and be reconciled to that person. Then come and offer your sacrifice to God." Matthew 5:23-24 NLT In v23 Jesus is likely talking about someone you have legitimately offended.  You probably did do something wrong and you need to go immediately and make it right.  Jesus says there’s more to this commandment than simply not murdering. We must tackle our anger by forgiving each other. Even if we are at the most sacred moment of our year—poised to offer a gift to God—forgiveness is more important. We must leave our gift and make peace with the person with whom we are so angry. (Knowles, Andrew. The Bible Guide.)