How do we know the Gospel is the Word of God?

The assurance of the Gospel's divine origin is rooted in the experience of those who receive it in faith. 1 Thessalonians 2:13 reveals that the Thessalonians accepted Paul's message as God's own word, not as mere human wisdom. This acceptance is evidenced by how the Word works effectually in those who believe, producing faith and transforming lives. It's ultimately the Holy Spirit that opens hearts to recognize this truth, and it is through the Gospel that God communicates His saving grace and empowers believers to live in accordance with His will.