Charles Spurgeon Commentary Mark 14:31

"But he spake exceedingly vehemently, If I must die with thee, I will not deny thee. And in like manner also said they all." — Mark 14:31 (ASV)

Likewise also said they all.

Whenever a man, who is called to be a leader, goes astray, others are pretty sure to follow him. It was so on this occasion, for when Peter made his boastful speech, Likewise also said they all, all the rest of his brothers chimed in, and so shared in his sin, but he was chief in the wrong-doing, for he led them all. In verse 53, we read what happened after Christ's agony and betrayal in Gethsemane: