Charles Ellicott Commentary Matthew 20:21

"And he said unto her, What wouldest thou? She saith unto him, Command that these my two sons may sit, one on thy right hand, and one on thy left hand, in thy kingdom." — Matthew 20:21 (ASV)

The one on your right hand—The favor that had already been bestowed might, in some degree, seem to justify the request. John was known emphatically as the disciple whom Jesus loved (John 13:23; John 19:26; John 20:2), and if we may infer a general practice from the Last Supper (John 13:23), he sat near Him at their customary meals. James was one of the chosen three who had been witnesses of the Transfiguration (Matthew 17:1). Both had been marked out for special honor by the new name of the Sons of Thunder (Mark 3:17).

The mother might well think that she was merely asking for her sons a continuation of what they had enjoyed until now. The sternness of our Lord’s words to Peter (Matthew 16:23) might almost justify the thought that his position had been forfeited.