Yesaya 22:22

22:22 I will place the key ¹  to the house of David on his shoulder. When he opens the door, no one can close it; when he closes the door, no one can open it.

[22:22]  ¹ sn This may refer to a literal insignia worn by the chief administrator. Even so, it would still symbolize the administrator’s authority to grant or exclude access to the king. See J. N. Oswalt, Isaiah (NICOT), 1:422.