'Key' in the Bible

They waited until they were ashamed; and behold, he didn't open the doors of the upper room: therefore they took the key, and opened [them], and behold, their lord was fallen down dead on the earth.

I will lay the key of the house of David on his shoulder. He will open, and no one will shut. He will shut, and no one will open.

Woe to you lawyers! For you took away the key of knowledge. You didn't enter in yourselves, and those who were entering in, you hindered."

"To the angel of the assembly in Philadelphia write: "He who is holy, he who is true, he who has the key of David, he who opens and no one can shut, and who shuts and no one opens, says these things:

The fifth angel sounded, and I saw a star from the sky which had fallen to the earth. The key to the pit of the abyss was given to him.

I saw an angel coming down out of heaven, having the key of the abyss and a great chain in his hand.