The main proof of Muhammad’s Prophethood, peace and blessings be upon him, is and forever will be the Miraculous Qur’an which was revealed by God to him through the Angel Gabriel. God Almighty, out of His mercy for the Jews and Christians (respectfully referred to in the Qur’an as the People of the Book) also provided an additional proof to mankind of his Prophethood. This can be found in their very own scriptures, the Torah and Gospels.
This video discusses the 42nd chapter of the Old Testament Book of Isaiah which clearly foretells the coming of an Arabian Prophet, specifically Prophet Muhammad (Peace be upon him).
To learn more about Muhammad in the Bible please visit their website:
http://www.manyprophetsonemessage.com/2014/06/28/muhammad-pbuh-and-madinah-in-the-bible/
My video is at DLive