But Isaac did not die as an offering as the blood of a testator, and blood was required to seal it, because as Paul said, "For where a testament is, there must also of a necessity be the death of the testator", and "Whereupon neither the first testament was dedicated without blood." (Hebrews 9:16-18). God provided a "ram" to be the replacement blood sacrifice for Abraham's son Isaac (Gen.22). Our Lord Jesus Christ "Immanuel" ('God with us'; Matt.1:23) was to eventually be That Replacement Sacrifice, instead of Isaac or the ram Abraham sacrificed. Our Lord and Savior was there with Abraham, to tell him about it. "Really?", some might say, "Where was Jesus mentioned in Abraham's day"?
     Please turn to Hebrews 7:

Heb 7:1    For this Melchisedec, king of Salem, priest of the Most High God, who met Abraham returning from the slaughter of the kings, and blessed him;
2    To whom also Abraham gave a tenth part of all; first being by interpretation King of righteousness, and after that also king of Salem, which is, King of peace;
3    Without father, without mother, without descent, having neither beginning of days, nor end of life; but made like unto the Son of God; abideth a priest continually.

     There is only One Who is "without father, without mother, without descent, having neither beginning of day, nor end of life; but made like unto the Son of God". I wonder who that could be? And Abraham tithed to this Melchisedec after returning from the slaughter of the kings, as per Genesis 14:

Gen 14:18    And Melchizedek king of Salem brought forth bread and wine: and he was the priest of the Most High God.
19    And he blessed him, and said, "Blessed be Abram of the Most High God, possessor of heaven and earth:
20    And blessed be the Most High God, Which hath delivered thine enemies into thy hand. And he gave him tithes of all."

     The "Bread" and "Wine" are Sacrements of Holy Communion with Christ Jesus. Why would they be mentioned here, and associated with this Melchizedek? Now back to Hebrews 7 continuing about this Melchizedek:

Heb 7:4    Now consider how great this man was, unto whom even the patriarch Abraham gave the tenth of the spoils.

     Paul is getting ready to reveal a very deep mystery about this Role of Melchizedek, because His receiving tithes of Abraham didn't fit into the requirements of the Old Covenant Law:

Heb 7:5    And verily they that are of the sons of Levi, who receive the office of the priesthood, have a commandment to take tithes of the people according to the law, that is, of their brethren, though they come out of the loins of Abraham:
6    But he whose descent is not counted from them received tithes of Abraham, and blessed him that had the promises.

     But this Melchizedek, king of Salem, during Abraham's day wasn't even descended of Abraham's people, yet He still received tithes from Abraham, and even had Power and Authority to bless ole' Abraham! Who was this Mysterious Person with such Authority at that time?

Heb 7:7    And without all contradiction the less is blessed of the better.

     Paul is just saying that it would be a contradiction for someone who has nothing, to try and bestow wealth and blessings onto One Who already 'owns' everything. Wonder Who already 'owns' everything? Are we getting closer to discovering Who this Melchizedek was during Abraham's time? Let's keep going further: