Paul

Paul of Tarsus — the apostle who transformed Christianity from a Jewish sect into a universal religion — whose epistles form the theological core of the New Testament and whose doctrines of grace and justification by faith define Protestant Christianity.

Made the crucifixion and resurrection of Jesus the center of Christian theology — not Jesus's ethical teachings but the salvific event of his death and resurrection — and argued that faith in this event, not observance of Jewish law, is the basis of salvation.