How do we know that only Jesus can please God?

The uniqueness of Jesus Christ in pleasing God is evident because He is the only one who has perfectly fulfilled the requirements of the law and lived without sin. In Matthew 3:17, God explicitly states that He is well pleased with His Son. The Gospel affirms that Jesus, being fully God and fully man, perfectly embodied righteousness and holiness, which no human can achieve on their own. Romans 8:3 reinforces this by stating that God sent His Son in the likeness of sinful flesh to condemn sin in the flesh for us. Thus, anyone who is in Christ shares in His righteousness, making them pleasing to God.