κρούω

He knocked at the outer gate, and a servant girl named Rhoda came to answer it.

But Peter kept on knocking, and when they opened the door and saw him, they were astounded.

So I tell you: Ask, and it will be given to you; seek, and you will find; knock, and the door will be opened to you.

For everyone who asks receives; he who seeks finds; and to him who knocks, the door will be opened.

Then you will be like servants waiting for their master to return from the wedding banquet, so that when he comes and knocks, they can open the door for him at once.