Charles Ellicott Commentary Isaiah 22:22

"And the key of the house of David will I lay upon his shoulder; and he shall open, and none shall shut; and he shall shut, and none shall open." — Isaiah 22:22 (ASV)

And the key of the house of David will I lay upon his shoulder ...—The key of the king's treasure-chambers and of the gates of the palace was the natural symbol of the chamberlain's or vizier's office, and, as in Isaiah 9:6, it was solemnly laid upon the shoulder of the new official, perhaps as representing the burden of the responsibilities of the duties of his office. In the keys of the kingdom of heaven (Matthew 16:19), and again in Revelation 3:7, as well as in the custom of admitting a Rabbi to his office by giving him a key, we have a reproduction of the same emblem.

So he shall open, and none shall shut ...—These words vividly paint the supremacy of the office to which Eliakim was to be called. He alone was to decide who was to be admitted into the king's chamber and for whom the king's treasury was to be opened. In Revelation 3:7, this symbolism is reproduced in its higher application to the King of kings.