2 Thessalonians 2:15
So then, brothers, stand firm and hold the traditions which you were taught by us, whether by word or by letter.
World English Bible (Public Domain)
In context
Before · 2 Thessalonians 2:13–14
13But we are bound to always give thanks to God for you, brothers loved by the Lord, because God chose you from the beginning for salvation through sanctification of the Spirit and belief in the truth, 14to which he called you through our Good News, for the obtaining of the glory of our Lord Jesus Christ.
15So then, brothers, stand firm and hold the traditions which you were taught by us, whether by word or by letter.