“Will rolled up his sleeves. "We'll probably have to knock down the door--"
"Or," said Jem, reaching out and giving the knob a twist, "not."
The door swung open onto a rectangle of darkness.
"Now, that's simply laziness," said Will.”

“Don't simply knock and wait for the door to be opened. Go look for the keys. Some fit the lock better than others.”

“Yeah, I said, swallowing and looking out my open door, at the ocean. The answer's yes.”

“They are so busy knocking that they do not notice that the door is open!”

“The doors will be opened to those who are bold enough to knock.”

“The door swung smoothly open, surprising her. A girl stood there. Barefoot. Dressed in a trash bag.”

“There was no warning, not even a knock. The door flew open, and he forgot his present aches and pains in anticipation of what lay in store. The figure that stood in the door was not that of an enemy. It was worse. It was his mother.”

“The soldier came knocking upon the queen's door,
He said "I am not fighting for you any more."”

“When the devil comes knocking on your door simply say "Jesus, it's for you.”

“Who’s there?”
“The scratcher of your itch,” he said.
She opened the door a crack and stuck her nose out. “Was that supposed to be romantic?”