John Chrysostom
And to those that are right-minded and have understanding, when revealed they appear good; but to those without understanding, they seem to be more deserving reverence because they are not understood.
Well is that said, Lest they turn; for they feign meekness that they may learn; and when they have learned, they attack.
Otherwise; The Lord had commanded us to love our enemies, and to do good to those that sin against us. That from this Priests might not think themselves obliged to communicate also the things of God to such, He checked any such thought saying, Give not that which is holy to the dogs; as much as to say, I have bid you love your enemies, and do them good out of your temporal goods, but not out of My spiritual goods, without distinction. For they are your brethren by nature but not by faith, and God gives the good things of this life equally to the worthy and the unworthy, but not so spiritual graces.
Otherwise; That which is holy denotes baptism, the grace of Christ’s body, and the like; but the mysteries of the truth are intended by the pearls. For as pearls are inclosed in shells, and such in the deeps of the sea, so the divine mysteries inclosed in words are lodged in the deep meaning of Holy Scripture.
Otherwise; The dog and the swine are unclean animals; the dog indeed in every respect, as he neither chews the cud, nor divides the hoof; but swine in one respect only, seeing they divide the hoof, though they do not chew the cud. Hence I think that we are to understand by the dog, the Gentiles who are altogether unclean, both in their life, and in their faith; but by the swine are to be understood heretics, because they seem to call upon the name of the Lord. Give not therefore that which is holy to the dogs, for that baptism and the other sacraments are not to be given but to them that have the faith. In like manner the mysteries of the truth, that is, the pearls, are not to be given but to such as desire the truth and live with human reason.
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If then you cast them to the swine, that is, to such as are grovelling in impurity of life, they do not understand their preciousness, but value them like to other worldly fables, and tread them under foot with their carnal life.
Or; The swine not only trample upon the pearls by their carnal life, but after a little they turn, and by disobedience rend those who offend them. Yea often when offended they bring false accusation against them as sowers of new dogmas. The dogs also having trode upon holy things by their impure actions, by their disputings rend the preacher of truth.
With good reason He forbade pearls to be given to swine. For if they are not to be set before swine that are the less unclean, how much more are they to be withheld from dogs that are so much more unclean. But respecting the giving that which is holy, we cannot hold the same opinion; seeing we often give the benediction to Christians who live as the brutes; and that not because they deserve to receive it, but lest perchance being more grievously offended they should perish utterly.