How do we know God's grace protects us from being deceived?

The assurance of God's grace as a protective measure against deception is found throughout the Scriptures. Paul asserts that confidence in our flesh leads to deception, but when we rely solely on the grace of God, we are preserved. In Romans 9:33, Paul quotes Isaiah, affirming that faith in the chief cornerstone—Jesus Christ—grounds us in truth and prevents confusion and shame. It emphasizes that our hope and righteousness must rest entirely on Christ's finished work, not on our actions or beliefs.