John Chrysostom

After this, to obtain yet more acceptance for His saying, He establishes it not by the honor only, but also by the punishment, going on to say, "And whoso shall offend one of these little ones, it were better for him that a millstone were hanged about his neck, and that he were drowned in the depth of the sea." "For as they," saith He, "who honor these for my sake, have heaven, or rather an honor greater than the very kingdom; even so they likewise who dishonor them (for this is to offend them), shall suffer the extremity of …

Homily on the Gospel of Matthew 58 ↗

Augustine of Hippo

Otherwise; Whoso offendeth one of these little ones, that is so humble as He would have his disciples to be, by not obeying, or by opposing, (as the Apostle says of Alexander,) it were better for him, that a millstone should be hanged about his neck, and he be drowned in the depths of the sea, (2 Tim. 4:15.) that is, it were better for him that desire of the things of the world, to which the blind and foolish are tied down, should sink him by its load to destruction.

Catena Aurea by Aquinas ↗

Jerome

But whoever causes one of these little ones who believe in me to sin, it would be better for him if a millstone were hung around his neck and he were drowned in the depth of the sea. Note that whoever is scandalized is little: for the greater ones do not receive scandals. Let him be hanged with a millstone around his neck, and let him be thrown into the depths of the sea. …

Commentary on Matthew ↗

Gregory the Dialogist

Otherwise; What is denoted by the sea, but the world, and what by the mill-stone, but earthly action? which, when it binds the neck in the yoke of vain desires, sends it to a dull round of toil. There arc some who leave earthly action, and bond themselves to aims of contemplation beyond the reach of intellect, laying aside humility, and so not only throw themselves into error, but also cast many weak ones out of the bosom of truth. …

Catena Aurea by Aquinas ↗