Whose high priest was Melchizedek?
Melchizedek was the High Priest of the Most High God, not of Israel or the Mosaic priesthood. Because Israel was not yet on the scene, he functioned as High Priest of the whole human race and pictured the priesthood Christ would fulfill.
Les teaches that Melchizedek brought bread and wine, which was unusual because bread and wine were not part of tabernacle worship or the Old Testament economy; they pointed ahead to Christ's death, burial, and resurrection—His broken body and shed blood. Abraham likely had no concept of what Melchizedek was doing, but God did, knowing the end from the beginning. Melchizedek was not a priest of Judaism, Moses, or Aaron, but a priest of the Most High God. Les explains that the term "Most High God" refers not just to Israel but predominantly to the non-Jewish world, as when Nebuchadnezzar called Daniel's God the Most High rather than Jehovah. Since Israel was not yet on the scene, Melchizedek was High Priest of the whole human race and a picture of the priesthood Christ would fulfill. The Day of Atonement high priest, entering behind the veil with blood and laying sins on the scapegoat, further illustrates that priesthood.