Charles Ellicott Commentary Mark 8:38

"For whosoever shall be ashamed of me and of my words in this adulterous and sinful generation, the Son of man also shall be ashamed of him, when he cometh in the glory of his Father with the holy angels." — Mark 8:38 (ASV)

Whosoever therefore.—Here St. Mark differs from St. Matthew, who omits these words, and agrees, though not quite verbally, with St. Luke. It is obvious that general as the words are, they had a special bearing on those who, like Peter, and probably the other disciples, had shown that they were “ashamed” of the words which had just been spoken.

This adulterous and sinful generation.—The words are not found in St. Luke’s report, but they agree with language which our Lord had used before (Matthew 12:39; Matthew 16:4). Their force here lies in the contrast drawn between those from whose frown or scorn the disciples were now shrinking, and the bright hosts in whose presence the faithless should be put to shame when the Son of Man should come in His glory. They were to look on this picture and on that, and ask themselves which ordeal was the most terrible.