But if you don't forgive people, your Father will not forgive your wrongdoing. Matthew 5:15
That's one of those verses that sets you back on your heels! Did Jesus really mean that? I'd say yes and no. No, in the sense that I doubt if any of us will fully forgive everyone. None of us are that pure in our motives. Plus, we may have even forgotten a few people along the way that we should have forgiven but didn't. I don't think we have to lay awake nights worrying about that. If we had to be perfect forgivers to be forgiven then we'd be earning our forgiveness, wouldn't we?
But on the other hand, yes. If you aren't someone interested in forgiveness then you aren't someone interested in God. Forgiveness is at the core of who God is. It's only the hypocrite who says they love God yet refuses to forgive. Isn't that what John was saying...
If anyone says, "I love God," yet hates his brother, he is a liar. For the person who does not love his brother whom he has seen cannot love God whom he has not seen. 1 John 4:20
In an odd sort of way, one of the greatest ways we can get to know God is through being deeply offended. It's in learning to forgive that we learn the depth of our sinfulness (we don't want to forgive) and the magnitude of God's love. But in saying that I hope you find other ways to know God.