John Chrysostom

Having, you see, given them their mortal blow; and from the facts first, then from their own suffrage, then from the prophet having aggravated the charge, with them indeed He discourses not at all, incorrigibly disposed as they are now come to be, but directs His speech to the multitudes, so as to introduce His doctrine, great and high, and full of much strictness; and taking occasion from the former topic, He proceeds to insert that which is greater, casting out also the observance of meats. But see when. …

Homily on the Gospel of Matthew 51 ↗

Theophylact of Ohrid

He no longer converses with the Pharisees, as they were incurable, but with the multitude. Christ sees fit to honor the multitude by calling them to Himself so that they might accept His word, and He says, "Hear and understand," urging them to be attentive. As the Pharisees had blamed the disciples for eating with unwashed hands, the Lord speaks of food, saying that no food defiles a man. And if food does not defile, how much less does eating with unwashed hands? What defiles the inner man is to say those things which he should not. …

Commentary on Matthew ↗

Thomas Aquinas

And having called together the crowds to him, he said to them etc. Above, the Lord showed the Pharisees who were making accusations to be unworthy of reprehending the disciples, because they were involved in greater sins; but now, passing over them, he instructs others, so that what was said above, 11:25, may be fulfilled: you have hidden these things from the wise and prudent, and have revealed them to little ones. And first he instructs the crowds; second, the disciples, at then the disciples came to him etc. …

Commentary on Matthew ↗