"What thing soever I command you, observe to do it: you shalt not add thereto, nor diminish from it" (Deut. 12:32).
"Beware lest any man spoil you through philosophy and vain deceit, after the TRADITIONS OF MEN, after the rudiments of the world and not after Christ" (Col 2:8)
Scriptures vs. Mans traditions: The word "traditions" is found 13 times in the New Testament, but only in three cases does it carry a favorable connotation. In the other 10 passages, it incurs the disfavor of Christ and His Apostles.
In the three verses, where the term "tradition" is used favorably, it is evident that the Apostle Paul was talking about something which he and other inspired individuals had taught. Let's look at 1 Cor. 11:2, where we see Paul first using the term tradition in a positive light. "Now I praise you, brethren, that you remember me in all things, and keep the ordinances [traditions, principles; and instructions], as I delivered them to you." Here, the word traditions literally means, principles and instructions given to you from God's written word. The idea of being handed down orally from one generation to another, is not in this meaning.
The other two positive examples are found in 2 Thessalonians. "Therefore, brethren, stand fast, and hold the traditions [things already delivered] which you have been taught, whether by word, or our epistle" (2 Thess. 2: 15). That is the boundary we are to stay within. The third example says, "Now we command you, brethren, in the name of our Lord Jesus Christ, that you withdraw yourselves from every brother that walks disorderly, and not after the tradition which he received of us" (2 Thess. 3:6).
Paul and the other apostles did not involve themselves in syncretism. These scriptures are clear that Paul is not talking about keeping mans oral traditions handed down over the years, by word of mouth, but the literal, written word of God.
So we simply need to ask. Is what we do something that was established by the original Apostles or something that was added after what was taught and written by them? Anything added after the original 12 Apostles is to be taken as “added by mans tradition” and “after the rudiments of the world and not after Christ"
Before you ask that question, you'd better first ask how you know whether any book in your New Testament is really canonical Scripture. There's no inspired, apostolically-endorsed table of contents. If your only authority is what's written in the Scriptures, your authority for knowing that 2 Thess or 1 Cor is scripture at all rests on ... nothing.
Christ didn't give teaching authority to a book, and never commanded the writing of a single verse of the NT. He gave teaching authority to his disciples in the Great Commission, and 2 Tim 2:2 tells you that they passed that teaching authority on to those who came after them.
By the way ... what does the Bible call "the pillar and ground of the truth"?