And when they had mocked him, &c. These verses are explained in the note on Matthew 27:31-32.
Related Commentaries of Mark 15:20
Mark 15:20-21
20 And when they had mocked him, they took off the purple from him, and put his own clothes on him, and led him out to crucify him.
21 And they compel one Simon a Cyrenian, who passed by, coming out of the country, the father of Alexander and Rufus, to bear his cross.