A conservative Christian, who believes in the inerrancy (freedom from error) of the Bible, and the inspiration by God of its authors, might cite passages from the Bible as proof of his existence. The gospels link Jesus' birth and crucifixion to historical persons and events. They describe his sayings, conversations, prayers and actions in great detail.
Many liberal Christians view Jesus as a great Jewish prophet and innovative, itinerant teacher. Even though they do not necessarily consider him divine, few ever question his existence.
Muslims also believe that Jesus was a great prophet. They do not believe that he died on the cross, but they definitely accept that he was born of a virgin, lived in Palestine in the early 1st century CE, and ascended to heaven without having previously died.
Many Jewish theologians regard Jesus as an itinerant rabbi of the 1st century CE who popularized many of the beliefs of the Pharisees and of the liberal Jewish thought at the time