Marcionism makes a comeback

I recently came across this interesting quotation from A J Heschel's "The Insecurity of Freedom:"

The spiritual alienation from Israel is most forcefully expressed in the teaching of Marcion, who affirmed the contrariety and abrupt discontinuity between the God of the Hebrew bible and the God whom Jesus had come to reveal.

Marcion wanted a Christianity free from any vestige of Judaism. He saw his task as that of showing the complete opposition between the Hebrew Bible and the Gospels.

Although in the year 144 of the Christian Era the church expelled the apostle of discontinuity and anathematized his doctrines, Marcion remains a formidable menace, a satanic challenge. In the modern Christian community the power of Marcionism is much more alive and widespread than is generally realised...

According to Rudolf Bultmann (as summarized by Bernhard W Anderson), "for the Christian the Old Testament is not revelation, but is essentially related to God's revelation in Christ as hunger is to food and despair is to hope... The God who spoke to Israel no longer speaks to us in the time of the new Covenant." Here is the spiritual resurrection of Marcion. Was not the God of Israel the God of Jesus? How dare a Christian substitute his own conception of God for Jesus' understanding of God and still call himself a Christian!"