John Chrysostom — as excerpted in the Catena Aurea on John 18:15-18

“(Hom. lxxxiii) But that Peter would have entered the palace, if he had been permitted, appears by what immediately follows: Then went out that other disciple who was known to the high priest, and spake unto her who kept the doors, and brought in Peter. He did not bring him in himself, because he kept near Christ. It follows: Then saith the damsel that kept the door unto Peter, Art not thou also one of this Man’s disciples? He saith, I am not. What sayest thou, O Peter? Didst thou not say before, I will lay down my life for thy sake? (Mat. 26:35) What then had happened, that thou givest way even when the damsel asks thee? It was not a soldier who asked thee, but a mean porteress. Nor said she, Art thou this Deceiver’s disciple, but, this Man’s: an expression of pity. Art not thou also, she says, because John was inside.”