'Knock' in the Bible

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

Once the head of the house gets up and shuts the door, then you will stand outside and start to knock on the door and beg him, 'Lord, let us in!' But he will answer you, 'I don't know where you come from.'