Be ye followers of me, even as I also am of Christ. Now I praise you, brethren, that ye remember me in all things, and keep the ordinances, as I delivered them to you.
1 Thess. 2:13
For this cause also thank we God without ceasing, because, when ye received the word of God which ye heard of us, ye received it not as the word of men, but as it is in truth, the word of God, which effectually worketh also in you that believe.
Therefore, brethren, stand fast, and hold the traditions which ye have been taught, whether by word, or our epistle.
And the things that thou hast heard of me among many witnesses, the same commit thou to faithful men, who shall be able to teach others also.
2 Thess. 3:14
“If any one refuses to obey what we say in this letter, note that man, and have nothing to do with him, that he may be ashamed”
“Take note of those who create dissensions and difficulties, in opposition to the doctrine which you have been taught; avoid them”
The Bible says in 2 Tim. 3:17 that the man of God is "perfect, furnished to every good work." As we noted above, this verse means only that the man of God is fully supplied with Scripture; it is not a guarantee that he automatically knows how to interpret it properly. This verse at most argues only for the material sufficiency of Scripture, a position which is held by some Catholic thinkers today.
"Material sufficiency" would mean that the Bible in some way contains all the truths that are necessary for the believer to know; in other words, the "materials" would thus be all present or at least implied. "Formal sufficiency," on the other hand, would mean that the Bible would not only contain all the truths that are necessary, but that it would also present those truths in a perfectly clear and complete and readily understandable fashion. In other words, these truths would be in a useable form," and consequently there would be no need for Sacred Tradition to clarify and complete them or for an infallible teaching authority to interpret them correctly or "rightly divide" God’s word.