How do we know the doctrine of gospel rest is true?

The truth of the doctrine of gospel rest is anchored in the Scripture's integrity, particularly in the book of Hebrews. The author clearly outlines that the promise of entering God's rest is contingent upon belief—specifically, faith that aligns with the preaching of the gospel. The failure of the Israelites to enter the Promised Land due to unbelief serves as a warning. Hence, the doctrine is authenticated as it reveals how true rest is only attainable through faith in Jesus Christ, the ultimate fulfillment of God's promises.