Behold, I stand at the door and knock.
Every part of that sentence is restraint. He is outside. He is stationary. He is making a sound and waiting, and the handle is on the other side.
This is addressed to a church, incidentally, not to outsiders. A group already convinced they were fine had somehow ended up with Christ on the wrong side of their own door, still knocking.
That is worth sitting with if you have been in this a long time. Familiarity is quite capable of closing a door without anyone deciding to.
What follows the knocking is oddly ordinary. He does not promise transformation or spectacle. He says He will come in and eat with them. A shared meal, the most domestic image available.
The knocking continues either way. He does not force the handle and He does not leave.
The only question is whether anyone inside answers.