Jesus was the Passover sacrifice whose bones were not broken (Numbers 9:12; John 19:32-36).
Both parts of this “prophecy” must apply if this is indeed a Messianic prophecy. Only the first part of the verse from Numbers is being used by missionaries as a proof of the supposed prophecy. The second part of this verse states that the Pesach sacrifice shall be made “in accordance with all the statutes connected with the Passover sacrifice.” Jesus was never placed upon a spit, Jesus was never roasted over a fire. Jesus was never eaten in the house with none of his flesh left over in the morning.
Jesus was lifted upon a pole to save mankind (Numbers 21:9; John 3:14-18).
The snake was not an object of worship. The copper snake was made as a way in encourage the people to look toward heaven and plead with God to save them. It was not meant as an object of worship. Yet, these verses in John show that Jesus is to be an object of worship! If anything is a prophecy that connects the copper snake and Jesus, it would be II Kings 18:4.
The snake was destroyed because the people began worshiping it instead of only worshiping God! Just like the theology of Christianity will be destroyed in the Messianic Age because it put Jesus on a stake and worshiped him instead of God.
Jesus was to be the future redeemer (Numbers 24:17; Galatians 4:4).
The beginning of the verse says “I see it, but not now; I behold it, but not soon.” This is not talking about an individual person.
This is also how Young’s Literal Translation translates this verse.
I see it, but not now; I behold it, but not near; A star hath proceeded from Jacob, And a sceptre hath risen from Israel, And hath smitten corners of Moab, And hath destroyed all sons of Sheth.
The very beginning of this verse is talking about the greatness and prominence of Jacob that will occur at a time in the future. The star is speaking of someone who will rise above all others. This is not talking about Jesus. The staff is referring to a ruler – a king. Jesus was never a ruler or king.
If this is a Messianic prophecy, both parts of the verse must be fulfilled. The second half of this verse reads “…which will crush the princes of Moab and uproot all the sons of Seth” Jesus did neither of these things. This is in fact a messianic prophecy. However, it is not about Jesus since he obviously did not fulfill this – or any other – prophecy regarding the Moshiach.
In the verse from Galatians, the word used for “born” in the Greek is γίνομαι (gen-oh-my). What makes that interesting is that word means to become, to arise, to appear in history, to be made, or finished. Christianity teaches that Jesus always existed. If he did then how could he be made or become or arise or finished?