Question: In Hebrews 7, the Bible says that Melchizedek was priest of the most high God, and he had neither beginning or ending, nor any father or mother. Is Melchizedek Jesus Christ in the Old Testament?
Answer: Let us look at the Scriptures given in your question:
"For this Melchizedek, king of Salem, priest of the most high God, who met Abraham returning from the slaughter of the kings, and blessed him." (1)
"Without father, without mother, without descent, having neither beginning of days, nor end of life; but made like unto (a type of ) the Son of God; abideth a priest continually." (3)
In Genesis 14:17-20 we have the actual event that Verse 1 is referring to. The only other place Melchizedek is mentioned in the Old Testament is found in Psalms 110:4, a Messianic Psalm.
"...Thou (Christ) art a priest forever after the order of Melchizedek."
No, Melchizedek was not Christ; BUT, was made "like unto," as Christ did have a father and mother. Therefore, the priesthood of Melchizedek was a type of Christ and His priesthood. Melchizedek father and mother were not priests before him; nor did he leave any children after him to become priests. His priesthood began and ended with him, just as Christ's priesthood begins and ends with Him.
You might take notice in Hebrew 7:24 where we are told,
"But this man (Christ), because he continueth ever, hath an UNCHANGEABLE priesthood."
The Greek word for "unchangeable" is "aparabatos" and this is the only place it appears in the Greek New Testament. It literally means "untransferrable"; therefore, the priesthood of Christ cannot and will not be changed to, or transferred to, any other person. There is no priest, or priesthood, that is ordained of God today. This is why in Matthew 27:50,51 it is recorded that,
Jesus, when he had cried again with a loud voice, yielded up the Ghost." (50) And, behold, the veil of the temple was rent in twain, from the top to the bottom... (51)"
The blood which Christ shed, opened a new and living way to God (Hebrews 10:19-25). Therefore, we now have direct access to God through our Lord Jesus Christ, who is our only mediator. This is made perfectly clear in 1 Timothy 2:5.
"For there is one God, and ONE MEDIATOR between God and men, the man Christ Jesus."