New Defender's Study Bible Notes
22:22 the key. The “key,” hanging on the shoulder, was symbolic of governmental authority (compare Isaiah 9:6), giving access to the treasures of the kingdom. Eliakim becomes a type of Christ, who alone has full authority over “the house of David.”
22:22 none shall open. This particular authority of Eliakim is quoted, in Revelation 3:7, 8, assuring faithful believers in Christ that it is Christ alone, having the key of David, who can open and shut doors.
22:23 a sure place. The “nail in a sure place” (note Ezra 9:8) speaks of stability in a time of trouble. Eliakim filled that role for a time and, in that way, was a type of Christ. However, even that would eventually be broken off (Isaiah 22:25), when Judah was finally sent into captivity.