This verse adds nothing new; its function is to emphasize by repetition (though in other words) you learned from us how you should live and in the name of the Lord Jesus from verse 1. Because of this emphasis, verses 1-2 fulfill something of the same function as a large-type heading in a modern newspaper. Verse 2 looks back to Paul’s oral teaching in Thessalonica, but (more important though less explicit) it also looks forward to the more detailed specification of God’s will which will begin in verse 3. Paul often tactfully reminds his readers of what he presumes they know already (cf. 1.5; 3.3, 4; 5.2).

You know the instructions we gave you may be rendered as “you know what we told you you should do,” or “you know how we told you you should live.”

By the authority of the Lord Jesus (cf. Moffatt) means virtually the same as in the name of the Lord Jesus in verse 1. The variation is one of style, not of content. Revised Standard Version‘s literal translation “through the Lord Jesus” (cf. King James Version) is unnecessarily misleading. Paul is not saying that Jesus is an intermediary between himself and the Thessalonians. By the authority of the Lord Jesus may be rendered in some languages as “these instructions came from the Lord Jesus” (cf. Translator’s New Testament), “this is just what the Lord Jesus said should be done,” or “this is what the Lord Jesus said we should tell you.” However, this last expression may suggest a connection between Paul and the Lord Jesus which would be too immediate.

After the introductory verses 1-2, Paul specifies two matters on which he exhorts his readers: sexual morality (vv. 3-8) and Christian fellowship (vv. 9-12).

Quoted with permission from Ellingworth, Paul and Nida, Eugene A. A Handbook on Paul’s First Letter to the Thessalonians. (UBS Handbook Series). New York: UBS, 1976. For this and other handbooks for translators see here .