Charles Spurgeon Commentary John 18:15-16

"And Simon Peter followed Jesus, and [so did] another disciple. Now that disciple was known unto the high priest, and entered in with Jesus into the court of the high priest; 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." — John 18:15-16 (ASV)

That disciple was known unto the high priest, and went in with Jesus into the palace of the high priest. But Peter stood at the door without.

John boldly followed Jesus, and so was safe. Peter stood at a distance from his Lord, and so was in danger.

That disciple was known to the high priest, and went in with Jesus into the palace of the high priest. But Peter stood at the door outside. Then went out that other disciple, who was known to the high priest, and spoke to her who kept the door, and brought in Peter.

I always imagine that John had a greater tenderness for Peter because he was the means of getting him into the palace of the high priest. Peter could not have gotten in if he had been alone, but John was known to the high priest, and so secured his admission. He must always have felt sorry that he took Peter into a place where he was so strongly tried. Hence John sought him out after his great fall; when perhaps the other apostles were inclined to leave him by himself, John cheered him up, and brought him back to the faith.