How do we know that salvation is by faith?

Salvation by faith is emphasized throughout scripture, particularly in the book of Hebrews, where the inadequacy of works and the necessity of faith in God's promises are highlighted. The Israelites in the wilderness provide an example of how unbelief kept them from entering into God's rest, while the faithful, like Joshua and Caleb, reinforce the truth that entering rest comes through trusting in God's word. Paul connects the Gospel with this notion of faith, asserting that 'unto us was the gospel preached as well as unto them,' aligning belief with acceptance of God's promises for salvation.