Except in the bible, and in the writings of the church fathers which were written after HIS church was orally established.
That's not replying to the point you quoted? There are precisely two claimed references by Jesus to ekklesia in one gospel written some half a century after he's meant to have died. Both references are to future events ("if your brother sins" and "I will build"). If there was one church, why is there no evidence for it in doctrine? Why the debate over Jews and Gentiles if Jesus has already established a church? Later on, sure, a church develops and ultimately you get a formal creed established. But it takes centuries and there's debate every step of the way there - debate on who Jesus was, on who God was, who one should listen to when teachings are changed, who one shouldn't listen to, even over the basics of what Jesus was meant to have said. If you're looking for the one true version of Christianity in that, good luck! Try Judaism!