Mark 15:21

(ubi sup.) Or, since this Simon is not called a man of Jerusalem, but a Cyrenian, (for Cyrene is a city of Libya,) fitly is he taken to mean the nations of the Gentiles, which were once foreigners and strangers to the covenants, but now by obedience are heirs of God, and joint heirs with Christ. Whence also Simon is fitly interpreted 'obedient,' and Cyrene 'an heir.' But he is said to come from a country place, for a country place is called 'pagos' in Greek, wherefore those whom we see to be aliens from the city of God, we call pagans. Simon then coming out from the country carries the cross after Jesus, when the Gentile nations leaving pagan rites embrace obediently the footsteps of our Lord's Passion.

Now John says that He Himself bare His cross, for both took place; for He first bore the cross Himself, until some one passed, whom they compelled, and who then carried it. But he mentioned the name of his sons, to make it more credible and the affirmation stronger, for the man still lived to relate all that had happened about the cross.

And they compel Simon a Cyrenian, who passed by, coming out of the country, the father of Alexander and Rufus, to bear his cross. Now since some men are known by the merits of their fathers, and some by those of their sons, this Simon, who was compelled to carry the cross, is made known by the merits of his sons, who were disciples. By this we are reminded, that in this life, parents are assisted by the wisdom and the merits of their children, wherefore the Jewish people is always held worthy of being remembered on account of the merits of the Patriarchs, Prophets, and Apostles. But this Simon who carries the cross, because he is compelled, is the man who labours for human praise. For men compel him to work, when the fear and love of God could not compel him.