John Chrysostom — as excerpted in the Catena Aurea on John 13:36-38

“(Hom. lxxii. 1) Peter, on receiving this answer, does not check his desire, but hastily conceives favourable hopes from it, and having got rid of the fear of betraying our Lord, feels secure, and becomes himself the interrogator, while the rest are silent: Peter said unto Him, Lord, why cannot I follow Thee now? I will lay down my life for Thy sake. What sayest thou, Peter? He hath said, thou canst not, and thou sayest, thou canst: wherefore thou shalt know by experience, that thy love is nothing, unless thou art enabled from above: Jesus answered him, Will thou lay down thy life for My sake?”