The woman at the door had just let Peter in at the word of another disciple, and she wanted to know whether he belonged to Jesus too. Her word "also" shows she counted Peter alongside at least one other follower of Jesus, though the text does not say whom she had in mind. Gill suggests she may have suspected him by his speech, by "the trouble that appeared in his countenance," or because she thought she had seen him with Jesus. Her question was not a threat. Matthew Henry points out that Peter would have had reason for alarm if Malchus had confronted him, but this was only a servant girl asking a question.

Peter answered with two words: "I am not" (John 18:17). Matthew Henry writes, "Without taking time to recollect himself, he suddenly answered, I am not." Then Peter went and stood with the servants and officers at their fire and "warmed himself" (John 18:18). This was the first of the three denials Jesus had foretold: "The cock shall not crow, till thou hast denied me thrice" (John 13:38). Two more would follow that same night (John 18:25-27).

The woman is called a paidiske, a female servant or maid, and a thyroros, a doorkeeper. Thayer defines the second word as a "doorkeeper, porter; male or female janitor." The same word is used of the porter who opens to the shepherd in John 10:3. In Greek her question begins with me, a negative word that frames the question as "you are not..., are you?" The ESV keeps that shape.

Matthew and Mark also say the first challenge came from a woman, a "damsel" and "one of the maids of the high priest" (Matthew 26:69; Mark 14:66). Commentators differ on who the "other disciple" was. Barnes says, "Not improbably John." Gill doubts that John could have been known to the high priest and suggests a secret believer among the rulers, perhaps Nicodemus or Joseph of Arimathea. The text leaves him unnamed.

John tells this story in two halves with Jesus' trial in between (John 18:15-18, 25-27). Inside, Jesus answers the high priest openly (John 18:20). Outside, Peter hides who he is. The contrast is the point: the Master stands firm while the disciple who had promised, "I will lay down my life for thy sake" (John 13:37), falls at the first question.

Gill notes what Peter did and did not deny. He did not deny that Christ was God or the Messiah; he denied that he was one of His disciples. Even so, Jesus had seen this coming before Peter did (John 13:38), and He still went on to the cross for him. Matthew Henry's Concise Commentary observes, "The beginning of sin is as the letting forth of water." One small denial opened the way to two more.