John Chrysostom

And together with these He mentions also another charge against them, that they are harsh to those accountable to them. "For they bind heavy burdens, and grievous to be borne, and lay them on men's shoulders, but they will not move them with their finger." He mentions here a twofold wickedness, their requiring great and extreme strictness of life, without any indulgence, from those over whom they rule, and their allowing to themselves great security; the opposite to which the truly good ruler ought to hold; in what concerns himself, …

Homily on the Gospel of Matthew 72 ↗

Theophylact of Ohrid

The Pharisees laid heavy burdens on men, forcing them to fulfill the commandments of the law which were detailed and difficult to observe. Indeed, they weighed them down with more than the commandments of the law by handing down certain traditions that went beyond the law; these traditions they did not move with even one of their fingers, that is, they themselves did not practice them, nor even dare to undertake such burdens. …

Commentary on Matthew ↗

Jerome

However, they bind heavy and burdensome loads and lay them on people's shoulders; but they themselves are unwilling to move them with their finger. This applies generally to all teachers who command heavy things but do not do smaller things. However, it should be noted that both the shoulders, the finger, the burdens, and the chains with which the burdens are bound should be understood spiritually.

Commentary on Matthew ↗

Thomas Aquinas

For they bind heavy and insupportable burdens, etc. For the Lord wishes to exaggerate their malice, because they say, and do not. If they simply said and did not do, this would still be tolerable; but this does not suffice them, because they add most grievous burdens to the precepts of God. …

Commentary on Matthew ↗

Glossa Ordinaria

Or, bind burdens, that is, gather traditions from all sides, not to aid, but to burden the conscience.

Catena Aurea by Aquinas ↗