Simon Peter followed Jesus - Natural though this was, and safe enough, had he only “watched and prayed that he enter not into temptation,” as his Master bade him (Mat 26:41), it was, in his case, a fatal step.
and ... another disciple - Rather, “the other disciple” - our Evangelist himself, no doubt.
known unto the high priest - (See on Joh 18:10).
went in with Jesus into the palace of the high priest.