Charles Spurgeon Commentary John 18:15

"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;" — John 18:15 (ASV)

And Simon Peter followed Jesus, and so did another disciple:

Here is John's usual modesty; he will not mention his own name, but simply speaks of "another disciple."

And Simon Peter followed Jesus, and so did another disciple:

That is John, of course; he never mentions his own name if he can help it.