blah blah blah, two thousand plus years of tradition going back to before the canon was established (by the early Catholics) blah blah. No where in the New Testament can we find the Trinity or can we find sola scriptura for that matter. Just made up stuff by Luther who before he died recognized that telling the common man to do it all on his own would result in lots of divergence. We now have 30K denominations of Protestants and still one, holy, catholic, and apostolic Church.
If the Trinity can not be found in the scriptures, it then is a myth...Just like all the fables of the mother of Jesus that your religion mandates you Catholics believe...
Fortunately we bible believers do see the Trinity in the scriptures or we wouldn't accept it...We see the doctrine of scripture alone as well...It's all over the bible...That's why we know it's true...