Theophylact of Ohrid — as excerpted in the Catena Aurea on Mark 13:3-8

“But before answering their question, He strengthens their minds that they may not be deceived, wherefore there follows: And Jesus answering them began to say, Take heed lest any man deceive you? And this He says, because when the sufferings of the Jews began, some arose professing to be teachers, wherefore there follows: For many shall come in my name, saying, I am Christ; and shall deceive many.”