How do we know Jesus fulfills the prophecies of the Old Testament?

Jesus fulfills the Old Testament prophecies in His life and work, most notably His incarnation, suffering, and resurrection. The prophet Zechariah's declaration that 'Thy King cometh' in Zechariah 9:9 is a powerful testament to His role as the Messiah. This is confirmed in the New Testament when Jesus rides into Jerusalem on a donkey, highlighting His humility and kingship. Romans 9:6 further clarifies that not all who are ethnically Israel are true Israel, emphasizing that the promises are fulfilled in the children of the promise, which includes all who believe in Christ. Thus, the fulfillment of prophecy in Christ establishes Him as the promised Savior.