To those who think that you can have Christianity (a way of life) without the historical Christ (God-man), Warfield replies:
Unquestionably, Christianity is a redemptive religion, having as its fundamental presupposition the fact of sin, felt both as guilt and as pollution, and offering as its central good, from which all other goods proceed, salvation from sin through an historical expiation wrought by the God-man Jesus Christ. The essence of Christianity has always been to its adherents the sinner’s experience of reconciliation with God through the propitiatory sacrifice of Jesus Christ. – B.B. Warfield in Christless Christianity
No Other Boast 