Augustine of Hippo — as excerpted in the Catena Aurea on John 6:60-71

“(Tr. xxvii. 8) Being cut off from the body, their life was gone. They were no longer in the body; they were created among the unbelieving. There went back not a few, but many alter Satan, not alter Christ; as the Apostle says of some women, For some had already turned aside after Satan. (1 Tim. 5:15). Our Lord says to Peter, Get thee behind Me. He does not tell Peter to go after Satan.”