How do we know that Jesus is the cornerstone?

In Mark 12:10-11, Jesus refers to Himself as the cornerstone, drawing upon Psalm 118:22-23. The stone that was rejected by the builders has become the essential foundation for all of salvation. This illustrates not only His significance in God's plan but also reflects the paradox of His rejection by the very people He came to save. The belief that He is the cornerstone is reiterated in the New Testament, particularly in the letters of Peter, emphasizing that faith in Him as the cornerstone leads to salvation and acceptance before God.