One place in the Old Testament where Christ is ‘concealed’ that most are familiar with is Genesis 14, where Melchizedek comes.
Genesis 14:18-20
Then Melchizedek king of Salem brought out bread and wine. He was priest of God Most High, and he blessed Abram, saying,
“Blessed be Abram by God Most High,
Creator of heaven and earth.
And praise be to God Most High,
who delivered your enemies into your hand.”
Then Abram gave him a tenth of everything.
The reason many people know this Old Testament story is because it is "revealed" in the New Testament, to show how Christ was foreshadowed by this mysterious king/priest of Salem.
Hebrews 7:1-3
This Melchizedek was king of Salem and priest of God Most High. He met Abraham returning from the defeat of the kings and blessed him, and Abraham gave him a tenth of everything. First, the name Melchizedek means “king of righteousness”; then also, “king of Salem” means “king of peace.” Without father or mother, without genealogy, without beginning of days or end of life, resembling the Son of God, he remains a priest forever.
Like Jesus, who is our King and our High Priest forever, Melchizedek was both the “king of peace” and “priest of God Most High”.
There is another, lesser known place in the Old Testament where we find reference to this unusual combination of priest and king. In the book of Zechariah, this prophet is told the following by the Lord:
Zechariah 6:11 – 13
Take the silver and gold, make an elaborate crown, and set it on the head of Joshua the son of Jehozadak, the high priest. Then speak to him, saying ‘Thus says the Lord of hosts, saying:
“Behold, the Man whose name is the BRANCH! From His place He shall branch out, and He shall build the temple of the Lord; Yes, He shall build the temple of the Lord. He shall bear the glory, and shall sit and rule on His throne; so He shall be a priest on His throne, and the counsel of peace shall be between them both.”
First of all, notice the name of this king and priest is Joshua, i.e. “Yeshua” (for more details please see my earlier entry “Would you name your child Jesus?”) – so how perfect is that? And here he seems to be using this Joshua as a symbol of the future Jesus (Yeshua), who is to come (one of the many names for the Messiah is ‘the Branch’). God is showing an earthly example - a 'concealed shadow' - in Joshua, to point to a future occurrence of when Jesus is revealed as both our High Priest and our King, to bring long-awaited peace to this stricken world.
Amen – Lord Jesus, come!