There are many prophecies in the Old Testament which had to be fulfilled with Jesus' first coming or the prophecy would be false. In Deuteronomy 18:20-22, we read, "But the prophet who presumes to speak a word in My name, which I have not commanded him to speak, or who speaks in the name of other god's, that prophet shall die. And if you say in your heart, 'How shall we know the word which the Lord has spoken?'-when a prophet speaks in the name of the Lord, if the thing does not happen or come to pass, that is the thing which the Lord has not spoken; the prophet has spoken presumptuously; you shall not be afraid of him." God through Moses states that a prophet must be 100% accurate (not 99.9%). If he is not then he is either killed (if he is still alive), or if not alive he is to be disregarded or nullified.

The Jewish people in the Talmud didn’t know how to combine the Messianic prophecies concerning the suffering servant Messiah (Jesus' first coming), whom they called Messiah ben Joseph, and the kingly, conquering Messiah(Jesus' second coming), whom they called Messiah ben David. But make no mistake they did consider the suffering servant Messianic (though almost 1000 years later, mostly by a famous Jewish commentator named Rabbi Rashi, they began to alter the interpretation of these prophecies). So let's look at some of the prophets who they would now have to disregard.

Isaiah: Isaiah 52:13-53:12. The Talmud referred to this strong presentation of the Suffering Servant as the Messiah

David: Psalm 22 which identified the Messiah as the Suffering Servant, and even described His death by crucifixion over 800 years before the Romans began using it widely as a form of capital punishment. Many other Psalms stated that the Messiah would be a direct descendant of David (this would be impossible for any future Messiah since all of the genealogies were destroyed when the Temple was destroyed in 70 AD). We have the genealogy of Jesus well marked out in Matthew and Luke.

Haggai: 2:6-9
Micah: 5:2
Zechariah: 12:10-12
Jeremiah: 23:5-6

The list goes on and on. But by using the instructions by God through Moses, you can see by the above list that most of the Old Testament would have to be disregarded by the Jewish people, if indeed these prophecies had not come true. In fact, Moses, who penned the entire Torah, or first 5 books of Scripture, would have to be disregarded since it was through him that Genesis 49:10 was written. But we know that they have all been fulfilled in Jesus. This should give us all tremendous confidence that God's Word is indeed God's Word.