'Key' in the Bible

They waited so long they were embarrassed, but he still did not open the doors of the upper room. Finally they took the key and opened the doors. Right before their eyes was their master, sprawled out dead on the floor!

They would spend the night in their posts all around God's sanctuary, for they were assigned to guard it and would open it with the key every morning.

I will place the key 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.