Bede the Venerable
Catena Aurea · Lukasevangelium 23
And when they were come to the place, which is called Calvary, there they crucified him, and the malefactors, one on the right hand, and the other on the left.
But the two robbers crucified with Christ signify those who under the faith of Christ undergo either the pains of martyrdom, or the rules of a still stricter continence. But they do this for eternal glory, who imitate the actions of the thief on the right hand; while they who do it to gain the praise of men, imitate the thief on the left hand.