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.
Thanks for the respect. I was speaking specifically of the Holy Trinity. A doctrine that is denied by some churchs. Such as Jehovah Witness, Mormons and Oneness Pentecostals. They will use Scripture to prove that there is no Trinity, and/or that Jesus is not God.
But Christianity also has the witness of the Early Church and what they believed and taught. These writings defend against the Arian and other heresies. That is why I say that using the Bible alone to argue for the Trinity doctrine may be ineffective. I do think that the Trinity and Christ's divinity.can be shown to be scriptural. But why not use the witness of those who learned from the Apostles or their students.
I was not speaking about the gift of salvation through Christ. That I would argue is very clear in Scripture. Both in the NT and the OT Psalms and Prophets.
However it is good to have arguments from outside of Scripture when dealing with people who do not regard the Bible as inspired and inerrant.
I found a good site called Darkness to Light which shows how the Church Fathers defended the doctrine of the Trinity. I think it is a site designed to answer challenges by JW's. It is non Catholic but I do not know if it is sponsored by any specific denomination.
You might find it interesting.
Here is the URL http://www.dtl.org/trinity/article/post-apostolic/pt-1.htm