The last word of 1 Thessalonians 2:13 is critically important: Paul states that the word of God is at work in you believers.
There were certainly some people in Thessalonica who heard the message of the gospel but did not experience God’s saving power (Acts 17:1–5). The reason is that they did not believe. This reality is conclusively demonstrated in the parable of the sower (Matthew 13:3–23; Mark 4:2–20; Luke 8:4–15). The same seed fell on four different kinds of soil, but only one of those soils produced fruit. The difference was not in the seed, but in the soil. In the same way, all kinds of people hear the word. It is the same word, God’s word, the gospel of his beloved Son; but many who hear do not experience its power. This is because they do not combine the word with faith. Thus Jesus concludes the parable of the sower with an urgent appeal to receive the message with a noble and good heart: He who has ears to hear, let him hear
(Luke 8:8, Luke 8:15).
It is essential, therefore, for us to think about the response that is required to the gospel and to the Scripture if they are to be effective in our lives. According to our text, Paul thanks God for the Thessalonians because they received his message not as the word of men, but as it actually is, the word of God.
It was pointed out in the exposition above that there were two aspects to the Thessalonians’ reception of the word: the objective, informational aspect, and the subjective response of acceptance and faith. It is the latter that we are referring to here.
13 And we also thank God constantly for this, that when you received the word of God, which you heard from us, you accepted it not as the word of men but as what it really is, the word of God, which is at work in you believers.