I just started reading The Grapes of Wrath by John Steinbeck. I found this bit of dialogue between protagonist Tom Joad and a burned-out country preacher to be interesting.
"There ain't no sin and there ain't no virtue. There's just stiff people do. It's all part of the same thing. And some of the things folks do is nice, and some ain't nice, but that's as far as any man got a right to say."
The former preacher continues,
"It's love. I love people so much I'm fit to bust,sometimes. An' I says, 'don't you love Jesus?' Well, I though an' thought' an finally I says, 'No, I don't know anybody name' Jesus. I know a bunch of stories, but I only love people."
Interestingly, The preacher's epiphany came when wrestling with his own hypocrisy. Failing to achieve victory over sin in his life, the former minister opts to deny sin's existence. With this framework it is only possible to view the gospel as an inspirational story. Genuine relationship with a character from a story is not possible.
Steinbeck's humanism is most explicitly stated later in the same conversation,
"I figgered, 'Why do we got to hang it on God or Jesus? Maybe,' I figgered, 'maybe it's all men an' all women we love; maybe that's the Holy Sperit - the human sperit- the whole shebang. Maybe all men got one big soul ever'body's a part of."
You will find similar lines of thinking in Genesis 3.