John Gill Commentary Mark 15:27

"And with him they crucify two robbers; one on his right hand, and one on his left." — Mark 15:27 (ASV)

And with him they crucified two thieves
For his greater reproach;

the one on his right hand, and the other on his left;
as if he had been one of them, and a principal among them; (See Gill on Matthew 27:38).