After God rebukes and demotes Shebna the steward (verses 15-19), He then fills his office with His servant, Eliakim. Eliakim means “whom God will raise up” or “the resurrection of God,” both of which apply to Jesus Christ. God gives Eliakim the substantial authority and responsibility that Shebna had. Verse 21 says he “shall be a father to the inhabitants of Jerusalem and to the house of Judah,” much as Joseph said, God “has made me a father to Pharaoh, and lord of all his house, and a ruler throughout all the land of Egypt” (Genesis 45:8). For both Eliakim and Joseph, their authority was exceeded by only one other person.
Take note of Isaiah 22:22, as Christ quotes it in the letter to the church at Philadelphia: “The key of the house of David I will lay on his shoulder; so he shall open, and no one shall shut; and he shall shut, and no one shall open.” Eliakim's authority to “open . . . and shut” results from “the key of the house of David” being put “on his shoulder.” We can compare this with Isaiah 9:6-7, another Messianic prophecy:
For unto us a Child is born, unto us a Son is given; and the government will be upon His shoulder. And His name will be called Wonderful, Counselor, Mighty God, Everlasting Father, Prince of Peace. Of the increase of His government and peace there will be no end, upon the throne of David and over His kingdom, to order it and establish it with judgment and justice from that time forward, even forever. The zeal of the LORD of hosts will perform this. (Emphasis ours throughout.)
The key of the house of David, then, represents God's governance, specifically His governance over Israel. The Bible even names the royal throne—the throne on which David and Solomon sat—as “the throne of the LORD” (I Chronicles 29:23; see II Chronicles 9:8)! God has sworn that David would always have an heir to sit on that throne (Jeremiah 33:17).
Thus, the key on Eliakim's shoulder represents the power of the government that would ultimately rest on the Messiah's shoulder. It involves the royal line of David and all the authority that resulted from God's covenant and promises to him. The Messiah would come from that same line, and He will sit on that throne when He returns and establishes His Kingdom (Isaiah 9:7).
In his position as second-in-command, Eliakim served as the ultimate gatekeeper, granting or denying access to the house of David at his discretion. He could open the door, and no one could shut it. Having the door opened meant access to the king's presence, and thus to the God-given authority and blessings of the royal line, as well as to all the resources of the treasury and storehouse. But if the steward shut the door, he blocked all of that access, and no one could overrule his decision.
It was a significant position. It is no wonder that God would not tolerate the likes of Shebna in it, who was more interested in his legacy and earthly pomp than fulfilling his office with gravity and faithfulness.
David C. Grabbe
The 'Open Door' of Philadelphia
Other Forerunner Commentary entries containing Isaiah 22:20: