Keys

17 And when I saw him, I fell at his feet as dead. And he laid his right hand upon me, saying unto me, Fear not; I am the first and the last:

18 I am he that liveth, and was dead; and, behold, I am alive for evermore, Amen; and have the keys of hell and of death…Revelation 1:17-18 (KJV)

More References: Matt. 16:19, Rev. 1:18