This verse deserves some unpacking. In the first place, Paul equates the message he proclaimed to the residents of Thessalonike with the word of God. Clearly the phrase refers to an oral proclamation here that was heard. If we ask what message Paul proclaimed, whatever else it contained, it surely contained the good news about Jesus, and perhaps in addition some quoting and exegeting of OT texts. Then Paul makes a remarkable statement. The Thessalonians received this proclamation as it actually was