In Revelation 3:7, the One who is holy and true holds the key of whom?

Answer: David

To Philadelphia: He holds the key of David; what He opens no one can shut, and what He shuts no one can open.

“To the angel of the church in Philadelphia write: These are the words of the One who is holy and true, who holds the key of David. What He opens no one can shut, and what He shuts no one can open.”— Revelation 3:7 (BSB)