2 Thessalonians 2:15

So then, brethren, stand fast, and hold the traditions which ye were taught, whether by word, or by epistle of ours.

Traditions" here does not refer in any manner to human traditions, but to the authentic teachings of the apostles as handed down orally, before the New Testament was available. Paul's use of yours" in this verse is not epistolary, but has reference to the apostles of Christ.