What does the Bible say about the effectual word of God?

In 1 Thessalonians 2:13, Paul expresses gratitude to God because the Thessalonians received the word of God not as the word of men, but as it truly is—the word of God. This underscores the importance of recognizing divine authority in the preaching of the gospel. The effectual nature of God's word means that it accomplishes that which God intends. When the gospel is preached, it can transform lives and bring about profound spiritual change, demonstrating the power and sovereignty of God in the process of salvation.