'Key' in the Bible

And they stay till confounded, and lo, he is not opening the doors of the upper chamber, and they take the key, and open, and lo, their lord is fallen to the earth -- dead.

And I have placed the key Of the house of David on his shoulder, And he hath opened, and none is shutting, And hath shut, and none is opening.

'Woe to you, the lawyers, because ye took away the key of the knowledge; yourselves ye did not enter; and those coming in, ye did hinder.'

'And to the messenger of the assembly in Philadelphia write: These things saith he who is holy, he who is true, he who is having the key of David, he who is opening and no one doth shut, and he shutteth and no one doth open!

And the fifth messenger did sound, and I saw a star out of the heaven having fallen to the earth, and there was given to it the key of the pit of the abyss,

And I saw a messenger coming down out of the heaven, having the key of the abyss, and a great chain over his hand,