For this cause. Or, “because of this.” Textual evidence may be cited (cf. p. 10) for the omission of “for.”
Thank we God. Compare on ch. 1:2, 3. Paul was assured of the reality of his converts’ initial faith, and he wanted to impress them with a sense of this reality lest they be tempted to doubt it and fall away from their faith.
Received. This word appears twice in this verse and is the rendering of two different Greek verbs. The first, paralamban, means the external reception, the hearing of the message; the second, dechomai, refers to the internal reception, the acceptance of the message.
Word of God. Paul had no doubts concerning the origin of the message he preached: he knew it came from God. He had also taught the Thessalonians from the sacred Scriptures (Acts 17:2, 3). He rejoiced that they also recognized the divine authority of his message, and quotes their recognition as a major cause for his own rejoicing.
Effectually worketh. Gr. energed (see on Phil. 2:13). When accepted into life, the word does its divinely appointed task.
In you that believe. The effectual working of the word operates in the Christian through faith. The word of God profits only when it is “mixed with faith” in those who hear (Heb. 4:2). The gospel is “the power of God unto salvation to every one that believeth” (Rom. 1:16). In one of Paul’s great benedictions, he tells how God is able to do for us far more than we can ask or think by “the power that worketh in us” (Eph. 3:20). Again, he speaks of his own experience, and tells how he strives in preaching with all the “energy” which God “mightily inspires” within him (Col. 1:29, RSV). In this case the mighty power of God’s word was working in the Thessalonian believers, giving them patience under trial and persecution.