6 You became imitators of us and of the Lord, for you welcomed the message in the midst of severe suffering with the joy given by the Holy Spirit.

Read 1 Thessalonians 1:6 Using Other Translations

And ye became followers of us, and of the Lord, having received the word in much affliction, with joy of the Holy Ghost:
And you became imitators of us and of the Lord, for you received the word in much affliction, with the joy of the Holy Spirit,
So you received the message with joy from the Holy Spirit in spite of the severe suffering it brought you. In this way, you imitated both us and the Lord.