Somebody is knocking should I let them in ?

Act 12:13 And as Peter knocked at the door of the gate, a damsel came to hearken, named Rhoda. Act 12:14 And when she knew Peter's voice, she opened not the gate for gladness, but ran in, and told how Peter stood before the gate. Act 12:15 And they said unto her, Thou art mad. But she constantly affirmed that it was even so. Then said they, It is his angel. Act 12:16 But Peter continued knocking: and when they had opened the door, and saw him, they were astonished.