15 And Simon Peter followed Jesus, and so did another disciple. Now that disciple was known to the high priest, and went with Jesus into the courtyard of the high priest.
16 But Peter stood at the door outside. Then the other disciple, who was known to the high priest, went out and spoke to her who kept the door, and brought Peter in.
17 Then the servant girl who kept the door said to Peter, "You are not also one of this Man's disciples, are you?"He said, "I am not."
18 Now the servants and officers who had made a fire of coals stood there, for it was cold, and they warmed themselves. And Peter stood with them and warmed himself.
Nine of the disciples scattered. Only John and Peter followed, and Peter did so far back (Matthew 26:58).
Peter stayed outside the high priest's palace (v. 16), probably because he was unknown and, therefore, not admitted. John was known (we aren't told how) and went inside, then came back and got Peter. (There is an outside possibility that the second disciple wasn't John. He wasn't recognized by the leaders in Acts 4:13, so how was he recognized here? And why didn't the girl question him too?)
The girl asked Peter if he was a disciple (v. 17). Surely she was no threat to him, but he still denied it. He was brave enough in the garden to take on the mob with his sword, but afraid before a girl. In Greek, the girl's question anticipated a negative response, making it easy for Peter to lie.
Inside the palace yard, the servants and officers who had arrested Jesus warmed by a fire (v. 18).
Peter's denials fulfilled Christ's prophecy (John 13:37-38; Matthew 26:33-35; Mark 14:29-31).