I think people are forgetting that using the Bible as a source of Trinity theology works fine with other Christians, but how do you explain the Trinity to Non Christians ? St. Patrick, St. Augustine and others were faced with that very issue.
Plus if Bible alone was sufficient to prove the Trinity we would not have the Jehovah Witness', The Mormons and Oneness Pentecostals. They too use the Bible as their proof text. The Arian heresy is alive and well.
With all due respect, I'd like you to list in great detail what tradition(s), not found in Holy Scripture, that are necessary for knowledge of how God has given us the gift of salvation through Christ.
I eagerly anticpate your response.
They don't have the bible, they just have a poor transliteration of the bible, the New World Translation.