How do we know the promise by faith of Jesus Christ is true?

The certainty of the promise by faith of Jesus Christ stems from God's character and His covenantal faithfulness. The Scripture, particularly in Galatians 3:22, concludes that all are under sin, yet through faith in Jesus Christ, believers are given the promise of salvation. This promise is grounded in God's eternal purposes and His unbreakable covenant with His people, which was fulfilled in the person of Jesus. Therefore, our assurance rests not on human efforts but on God's sovereign grace and the sufficiency of Christ's atonement for those whom He has chosen.