In the mouth of two or three witnesses shall every word be established. [2 Corinthians 13:1 KJV (TR undisputed)]
The establishing of truth by 'two or three witnesses' is attested by Moses, Deuteronomy 19:15, by Jesus of Nazareth, Matthew 18:16, by Paul the Apostle, 2 Corinthians 13:1 and by the writer to the Hebrews, Hebrews 10:28. So at least three witnesses agree on the validity of the statement.
As to my own faith in Jesus Christ, the Son of God, I have the witness of holy scripture, the Hebrew scriptures being zealously and jealously preserved throughout history and the Greek scriptures being providentially preserved in over five thousand documents, well nigh one hundred thousand quotations of 'Patristic Citation', thousands of Lectionary quotations and many translations into other languages particularly Old Latin, Syriac and Coptic.
But I also have a witness within to truth. There is a spirit within which manifests itself as being stronger than the human nature with which I came into the world, inherited from my natural parents. Once the law came and slaughtered me (see Romans Chapter 7) and once the knowledge of Jesus Christ (through a faith which works by love) was established within me, I came to realise a presence within which is stronger than nature.
Jesus Christ promised that the Spirit would come and would lead into all truth, John 16:13.
And so I find, for I am led in my studies and led in my understanding in a way that is very, very different from absorbing knowledge as at school or college. It is to the whole man. It is the 'forming of Christ within', Galatians 4:19.
This is not epistemological. It is not the tree of the knowledge of good and evil.
This is the Tree of Life. Or, so I find.
Then I have yet another branch of witness, for I find I am not alone in my faith and in my experience. I find myself keeping company, as it were, with Athanasius (328-373) with Martin Luther (1483-1546) with John Calvin (1509-1564) with John Hooper (1495, martyred in 1555) with John Bunyan (1628-1688) with William Huntington - a true father in the faith to myself - (1745-1813) with J C Philpot (1802-1869) with Dean John Burgon (1813-1888) with Herman Hoskier (1864-1938) with J K Popham (1905-1937) and with John Metcalfe (1931 and still not departed).
Time would fail to list all of this veritable cloud of witnesses. And this is not an intellectual agreement over points of doctrine, only. For I find also an agreement of experience. These men also attest to the Spirit within. It appears that we all 'drink into one Spirit', 1 Corinthians 12:13.
My faith is not a matter of my personal opinion. Nor is it a matter of personal logic, that is to say of my own epistomology.
My faith is founded on the attestation of three witnesses, the latter of which is a multiple testimony.
Is this agreed by present-day Protestantism - that each individual Christian has the benefit of two or three witnesses to fundamental truth ?