So then, brothers, stand firm and hold to the traditions that you were taught by us, either by our spoken word or by our letter.
- II Thessalonians 2:15
This verse has been used several times in the course of discussions on this blog as a kind of "proof text" showing that there were unwritten Apostolic traditions (i.e. traditions not recorded in the Bible). These authoritative traditions were handed down by word of mouth within the Christian churches. Thus it would seem that even the Bible admits to the falsity of Sola Scriptura, since it admits to the existence of extra-biblical authoritative traditions. But is this really the case? I believe that there are passages elsewhere in II Thess. itself that call this line of reasoning into question.
Do you not remember that when I was still with you I told you these things?
- II Thessalonians 2:5
For even when we were with you, we would give you this command: If anyone is not willing to work, let him not eat.
- II Thessalonians 3:10
In both of these verses Paul refers to a teaching that he had already given orally to the Thessalonian church. Yet he finds reason to repeat his teachings in writing. What is the significance of this? Well, for starters, it means that II Thess. 2:15 cannot necessarily be referring to oral traditions that were never written down as Scripture. Moreover, because we have a precedence for Paul repeating important teachings in Scripture, it is not at all unreasonable for the Protestant to assume 2 things, one weak and one strong. The weak assumption being that Paul also wrote down other oral teachings in Scripture, and the stronger assumption being that all oral teachings that were/are necessary to salvation, as well as church piety and practice, were also recorded as Scripture. Note, I have not argued that these verses in II Thess. actually prove this Protestant assumption correct, but they do make it reasonable (especially in light of other passages that deal with the place and purpose of Scripture itself), and they also refute the Catholic/Orthodox argument that the oral teachings Paul refers to must be teachings that are not included in Scripture.
Finally, I should mention that upon examination of II Thess. 2:15 itself, without reference to either 2:5 or 3:10, there is actually no indication given by Paul that when he says, "either by our spoken word or by our letter" he is referring to different teachings. Such a reading must be imposed on the text.