What is the origin of Baptism?

In the Gospels we find John the Baptist baptizing people in the Jordan River. But where did the concept of Baptism originate? Was this a command from God that we are not told about? Did John develop the concept of Baptism? Was baptism being done before the New Testament? Why was John baptizing people in the Jordan River? Because the Bible is silent on these issues, Churches have created their own doctrines concerning baptism.

EDIT 12/16/17: Thanks to Julie who emailed me and mentioned that the Greek word βαπτίζω (baptizo, #907) comes from the root word βάπτω (bapto, #911) and means to submerge. "Buried with him in baptism..." (Romans 6:3, 4, 5 and Colossians 2:12).

EDIT 12/16/17: David emailed me the following... The word ’baptism’ and its variations are based on Strong's number 907. #908 is NOT the word used in 1 Cor. #907 baptizo (Greek) (bap-tid’-zo); from a derivative of #911; to immerse, submerge; to make overwhelmed (i.e. fully wet); used only (in the N. T.) of ceremonial ablution, especially (technically) of the ordinance of Christian baptism: translated in the KJV-- Baptist, baptize, wash. #911 bapto (bap’-to); a primary verb; to overwhelm, i.e. cover wholly with a fluid; in the N. T. only in a qualified or specific sense, i.e. (literally) to moisten, or (by implication) to stain (as with dye): translated in the KJV-- dip.

Видео What is the origin of Baptism? канала Jeff A. Benner