Pidyon Haben and The Son of God.

The Laws of Pidyon Haben(redemption of the firstborn, Numbers 18:15) according to Jewish tradition began after the Egel haZahav(golden calf) incident. Before that the first born male of every tribe was to be set aside for Mishkan/Beis HaMikdash(Tabernacle/Temple) service(see Exodus 13:1-2, Exodus 24:5 with Rashi). The tribe of Levi was the only one that did not participate in the sin of the Egel haZahav so the whole tribe was dedicated to Mishkan/Beis HaMikdash service. So it seems that Pidyon Haben was a release, mandated by God, that every other tribe had to do regardless of whether or not the father of that child wanted his firstborn to become a priest. Christ not being of the tribe of Levi would have to have a Father that was not of any of the tribes that sinned with the golden calf and thus not be subject to the laws of Pidyon Haben making him eligible for the Priesthood.

The Akaidah and the Passion.

The Passion of the Christ is in many ways parallel with the Akaidah(Binding) story of Genesis 22. Christ carries the cross on His back to Calvary-Isaac carries the wood for the sacrifice. Isaac willingly allows himself to be the sacrifice for his father. Like Jesus and the Father, Abraham and Isaac are unified. There is also a sense of dispare in both willing "victims". Jesus crying "My God my God why have you forsaken me". And when Yaakov is confronted by Lavan after fleeing his home he says in Genesis 31:42 "Had not the God of Avraham and the Dread of Itzchak been with me..." After Crucifixion Christ disappears for a while before returning to His disciples- Isaac disappears from the narrative for a while until he reappears just before his wedding to Rebecca.