As we grow in our understanding of the Scriptures, we recognize that God uses typology in the Old Testament to foreshadow events or persons in the New Testament, particularly Christ and His salvation.
The shadowy character of Melchizedek is called a likeness of Christ as our king and priest (Heb. 7:15).
Abraham's near sacrifice of Isaac and his son rising up unharmed from the altar pictured the Father offering His Son at the cross and raising Him from the dead (Heb. 11:19).
The deliverance of Israel through Moses from Egypt's bondage typifies our deliverance by Christ from our bondage to sin. On and on the typologies roll.
Yet by their very nature, typologies are incomplete. As prophetic symbols, the type can never achieve the status of the antitype. Simply put, Melchizedek, Isaac, and Moses are not Jesus, but simply pictorial aspects of our Savior.
For this reason, then, the Spirit of God sometimes strings together typologies to give even richer imagery of our salvation in Christ. We could refer to these as double, or dual, typologies. We can see these double types in a variety of ways.
For instance, in the sacrifice of Isaac by Abraham, Christ is not the only person of the Godhead represented in the story. Certainly Isaac pictures the Lord, but Abraham also prefigures the plan and work of the Father in sending His Son to Calvary's cross. This truth is highlighted by God giving a ram to Abraham to offer instead, and Abraham in response named that site YHWH-jireh ("the Lord will provide"). That this mountain was the very place that became know as Calvary solidifies this glorious picture.
Sometimes the person of Christ is pictured by two related figures. Moses led Israel to the Promised Land, but because of his sin he was not allowed to take them into the land. He died and was buried by God. But then his predecessor Joshua rose up and conquered the land as the presence of God was with him (Josh. 1:8-9). These two personages together picture the deliverance and victory that come to us in Christ. That Moses is confirmed to be a type in the New Testament (Heb. 3:1-6), and that Joshua's name means "The Lord saves" of which Jesus' name is the Greek version of it, help connect further this imagery for us.
The work of Christ can also be pictured with this double emphasis, sometimes very simply so. For example, on the Day of Atonement two goats were brought before the high priest (Lev. 16:6-10). He cast lots for the goats, and one was deemed the goat for a sin offering and the other the scapegoat. After sins were confessed over both of them, the first goat was slain and offered before the Lord, whereas the second was sent off into the wilderness. As Jerry Bridges explains,
The first goat represented Christ’s work of propitiation as it was killed and its blood sprinkled on the mercy seat. The second goat represented Christ’s work of expiation in removing or blotting out the sins that were against us.
In other words, the former goat represents the Lord redeeming us from the penalty of sin; the latter goat on how the Lord is removing the presence of sin from our lives.
If we pray for the Spirit-enhanced eyes to see it, these dual typologies are pretty common in the Scriptures. Cain and Abel. David and Goliath. The tabernacle and the temple. The list could go on. These paired personalities or figures all teach us in tandem what the Lord has done for us. Like a double rainbow, they magnify His glory.