The first mention of the key of the house of David is found in the book of Isaiah, in a description of the duties of Eliakim, the royal chamberlain of King Hezekiah of Judah:
Isaiah 22:20 And it shall come to pass in that day, that I will call my servant Eliakim the son of Hilkiah:
Isaiah 22:21 And I will clothe him with thy robe, and strengthen him with thy girdle, and I will commit thy government into his hand: and he shall be a father to the inhabitants of Jerusalem, and to the house of Judah.
Isaiah 22:22 And the key of the house of David will I lay upon his shoulder; so he shall open, and none shall shut; and he shall shut, and none shall open.
The key of the house of David is upon his shoulder? What does that mean? Let Isaiah explain. Speaking about Jesus, Isaiah says:
Isaiah 9:6 For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace.
Isaiah 9:7 Of the increase of his government and peace there shall be no end, upon the throne of David, and upon his kingdom, to order it, and to establish it with judgment and with justice from henceforth even for ever. The zeal of the LORD of hosts will perform this.
The key of the house of David is symbolic for the government of Eliakim in Isaiah 22 (verse 21), which is a type or symbol of the government of Jesus Christ as described in Isaiah 9. Note also that according to Isaiah, the government or kingdom of Jesus Christ is established, or founded, on a work of judgment This is an important aspect of the key of the house of David, which will be explained.
Sir Godfrey Gregg