Coffman Commentaries on the Bible - John 18:16
But Peter was standing at the door without. So the other disciple who was known unto the high priest, went out and spake unto her that kept the door, and brought in Peter.The circumstance of John's being favorably known to the high priest was that which provided this eyewitness account and also resulted in Peter's admittance to the theater of his triple denial. Thus the question left dangling in the synoptics as to how Peter happened to be at the trial, or near it, is cleared up by this... read more
Coffman Commentaries on the Bible - John 18:15
And Simon Peter followed Jesus, and so did another disciple. Note that disciple was known unto the high priest, and entered in with Jesus into the court of the high priest.Simon Peter followed ... The synoptic version is that he did so "afar off" (Mark 14:54), still smarting, perhaps, from Jesus' command to put up his sword. See my Commentary on Matthew, Matthew 26:58, for an outline of the seven contributing causes of Peter's denial.And so did another disciple ... This refers to John, the... read more