Man cannot climb up a set of steps by going down them. He cannot go down a hill in order to get on top of a mountain peak. Yet in Ephesians 4:9 we read, "Now that he ascended, what is it but that he also descended first into the lower parts of the earth." Now take note of that word "first." Of course, one who descends can later on ascend. But do not forget that the descension here of Jesus was into death, the grave, and hell! How can one who goes down into death climb up to the life more wonderful than the one lost through that death?
Christ suffered the punishment we deserve because of our sins. He removed all our guilt, as our covenant Head and representative. He could and did arise and even ascend to heavenly glory, because He is the way appointed by God to redeem us. To redeem is to buy back our innocency. He also ascended to heavenly glory because He earned for us that higher glory of a closer covenant fellowship with God than Adam had.
Therefore we, who deserve to suffer all that He did on His cross, are not going to suffer one bit of the agony of punishment for sin. He did cry out, "My God, my God, why hast thou forsaken me?" But we will not be forsaken of God. We will be received by Him for covenant fellowship and blessedness. He descended to take away our guilt. He earned ascension for us, and cried out of this victory when He exclaimed, "It is finished!" The curse was finished; the punishment we deserve was removed in full.
No wonder then that Paul could write that He made captivity captive. Through His cross we are going to ascend to everlasting glory which is too wonderful for our present human language to describe.
His descension assures us of our ascension. We will not go down to hell in order to be lifted up to heaven. He captured hellish agony so that He could everlastingly keep it from us.
Read: John 14:1-21 .
William Hendrikson: "Scripture emphasizes the fact that the Church in both dispensations is one. It is one chosen people in Christ. It is one tent; one vineyard; one family—Abraham is the father of all believers whether they are circumcised or not—one olive tree; one elect race, royal priesthood, holy nation, people, for God’s own possession; one beautiful bride; and in its consummation one new Jerusalem whose gates bear the names of the twelve tribes and whose foundations are inscribed with the names of the twelve apostles" (More Than Conquerors, p. 135).