If any doubt should ever be applied into anything you (in general) must digest- it might as well be religions.
Any group or sect that obliges you to accept, without you ever questioning the very essence of the nature and n question, should really require you to place a whole hearted "doubt" upon the assertion. The question wether a Christ existed in those terms, should require a "ncsi" examination.
So, if I asked you..is God (biblical) good? I would expect you to reply, yes indeed. Ok- so where did evil come from (provided an evil exist under those biblical conditions)..you say from Satan, ok. Did God creat Satan? You say, yes indeed, ok. So, where did Satan get his evil from if God is good, and God would creat only good...right? What kind of God is this when he can't get his mess into place. Now would you continue to believe?