Pseudo-Chrysostom
Catena Aurea · Matthäusevangelium 7
Give not that which is holy unto the dogs, neither cast ye your pearls before swine, lest they trample them under their feet, and turn again and rend you.
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.