Charles Ellicott Commentary Matthew 27:28

"And they stripped him, and put on him a scarlet robe." — Matthew 27:28 (ASV)

A scarlet robe — Here again we have a technical term: the chlamys, or paludamentum. This was the military cloak worn by emperors in their role as generals and by other high-ranking officers (Pliny, xxii. 2, 3).

St. Mark and St. John call it purple (Mark 15:17; John 19:2), but the “purple” of the ancients was a crimson color, and the same garment could easily be described by either name. It was probably a cast-off cloak of Pilate’s own, or possibly the one in which Herod had previously dressed Him (Luke 23:11).

It was an all too common practice to subject condemned prisoners to this kind of outrage before their execution. Philo records a similar mockery practiced on a man with an intellectual disability in Alexandria, who was made to represent Herod Agrippa II (in Flacc. p. 980). The point of this mockery, of course, was that their victim had been condemned for claiming the title of a king. They had probably seen or heard of the similar insults offered by Herod and his soldiers (Luke 23:21) and now reproduced them with even greater cruelty.