Marcion, the Bishop of Sinope, is arguably the arch-heritic in the history of the church.
To Marcion, the person of Jesus was great, and so were his teachings. But the Old Testament and the Gospel of Jesus, Marcion argued, cannot be reconciled to each other. And in light of all these apparent contradictions, Marcion came to the only conclusion he could tolerate: we shouldn’t try to reconcile Jesus with the OT. Instead, let’s just dismiss out of hand the entire Hebrew Bible as something inspired by a lesser and juvenile god, not the Supreme God revealed as the Father of Jesus Christ.
And so Marcion spent 15 years of his life doing what no single follower of Jesus had done to date: he created a creed and compiled a single source of new scripture for the church, his version of our New Testament.
Marcion had gotten rid of what he didn’t like or what he didn’t understand, so that he could make God into his own image. Something we're all tempted to do. We're all tempted to be Marcionites at least a little bit.