How do we know Jesus fulfilled the covenant of grace?

The fulfillment of the covenant of grace by the Lord Jesus Christ is rooted in His atoning death, wherein He took our iniquities upon Himself. Scriptures like Isaiah 53 show that He was wounded for our transgressions and that by His stripes we are healed. The justice of God was satisfied, making it possible for His people to be considered righteous. This was an eternal promise, demonstrating that Jesus was not only the bearer of sin but also the justifier of those who believe in Him, thereby fulfilling the covenant that God established from everlasting.