'Shut' in the Bible

"To the angel of the church in Philadelphia write the following: "This is the solemn pronouncement of the Holy One, the True One, who holds the key of David, who opens doors no one can shut, and shuts doors no one can open:

I know your deeds. (Look! I have put in front of you an open door that no one can shut.) I know that you have little strength, but you have obeyed my word and have not denied my name.