John the Apostle
John 18:15BSB·traditional attribution

Now Simon Peter and another disciple were following Jesus. Since that disciple was known to the high priest, he also went with Jesus into the courtyard of the high priest.

John Calvin Reformed @genevareformer

15. And another disciple. Some have been led astray, by a slight conjecture, to suppose that this disciple was the Evangelist “Nostre Evangeliste.” John, because he is accustomed to speak of himself without mentioning his name. But what intimacy with a proud high priest could John have, who was a mean fisherman?

Matthew Henry Presbyterian @wholebiblehenry

We have here an account of Christ's arraignment before the high priest, and some circumstances that occurred therein which were omitted by the other evangelists; and Peter's denying him, which the other evangelists had given the story of entire by itself, is interwoven with the other passages.

Commenting on John 18:13-27

John Gill Reformed Baptist @doctorgill

And Simon Peter followed Jesus,.... It is certain, he first fled with the rest, and forsook him, as they all did, notwithstanding his resolution to abide by him; however, he was very desirous to know what would become of Jesus, and what would be the issue of things; with this view he followed him, and not to deny him; though that was the consequence.