Guys. Let me be frank. Melchizedek is not a real name. His name is actually a title. It is taken from 2 words. Melchi and Zedek. King and Righteousness. It is his title. King of Righteousness. He was also the King of Salem. Salem was the original name of Jerusalem before it became Jerusalem.
Traditional writings tells us that his real name is Shem. The firstborn of Noah. He too lived a long life like those before the flood. It’s important to note at the time of Abraham, Jerusalem did not exist.
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It only became the capital of Israel when King David made it so. Hence, it could not have been Jesus. He may be a shadow of how Jesus is but he is not Jesus.
When we refer to Hebrews 7 it is pertinent to note the context there is the contrast of the Levitical priesthood and that of Jesus. It is a contrast of Law and Grace. As such it is important for us to note that the Levitical priest had a term of service. As such they needed to carry certificates to proof that they are Levites. Hence there is a need to prove their ancestry.
Jesus is the priest under the priesthood of Melchizedek as promised to him in the Psalms. He has no beginning and end to his priesthood. It is not under Levi but Judah. His priesthood is base on an oath God made to him and hence has no need to prove his ancestry. So there is no need to show who his father is.
That is what the writer meant by he had no father and no mother. He is not saying that Jesus is Melchizedek.
The point that Hebrews 7 is trying to prove is this. The priesthood of Levi is of the Law and the priesthood of Jesus is of grace. The priesthood of the Law is coming to an end at that time and ended in AD70. The priesthood of Jesus is here to stay.
Since your priesthood last forever, he lives to be your righteousness forever. That’s why he and not the law, is able to save you completely.
If you keep harping that Jesus is Melchizedek, you will miss the whole point of that chapter. He was telling to Hebrews to leave the Old Covenant of the Levitical priesthood and embrace the New Covenant where Jesus is your High Priest.