Give not that which is holy to dogs; neither cast ye your pearls before swine, lest perhaps they trample them under their feet, and turning upon you, they tear you.
Praised be Jesus Christ!
Now and forever. Amen.
Continuing on with the same discourse, Jesus presents us with this bit of wisdom, "Give not that which is holy to dogs." Here, Jesus cautions us to be careful about sharing holy things to others. Why? Because they--the dogs and the swine--may trample it underfoot, and then turn on you.
Remember that Jesus has been discoursing about judgment. He begins by warning us not to condemn others, but to offer right judgement, because how we judge others will be how God judges us. Then, He continues by warning us that if we want to help others overcome their sins, we must first root out sins from our own lives. Now, He's warning us that, once we've cleaned out our eyes, to be careful about who we offer our help to. What help is that? That which is holy.
When we root out sins from our lives, we invite the Holy Spirit within. We become one with Jesus, who acts through us. Then, when we have received this, His holiness, into ourselves, we are called to pass it on, to share it with others. Then, we are now ready to help our brothers cast out the specks from their eyes.
However, we must now exercise right judgement. We cannot offer this holiness, we cannot offer Jesus and His Holy Spirit to everyone. Why? Because not everyone will treat with the right reverence and respect that gift which you offer to them. Jesus calls such people dogs and swine. Animals who will trample that which is holy underfoot. And since that holy gift which you offer is coming from you, because it is a gift which you first received, they will then turn against you and tear you down as well.
Jesus shows us this right judgement later in Matthew. He uses the same language and reminds us of this teaching.
" And behold a woman of Canaan who came out of those coasts, crying out, said to him: Have mercy on me, O Lord, thou son of David: my daughter is grieviously troubled by the devil.  Who answered her not a word. And his disciples came and besought him, saying: Send her away, for she crieth after us:  And he answering, said: I was not sent but to the sheep that are lost of the house of Israel.  But she came and adored him, saying: Lord, help me.
 Who answering, said: It is not good to take the bread of the children, and to cast it to the dogs.  But she said: Yea, Lord; for the whelps also eat of the crumbs that fall from the table of their masters.  Then Jesus answering, said to her: O woman, great is thy faith: be it done to thee as thou wilt: and her daughter was cured from that hour."
It may seem cruel for Jesus to speak this way to the woman, calling her a dog. His language was not personally directed, however, as we can understand now that He was referencing and earlier teaching that He had given. The woman was a dog not because she personally was a dog, but because she was a Canaanite--a non-believer. It is to the non-believe, the one who is an historical enemy of the Faith that we must exercise caution when offering the holy gift we have received.
This does not mean, of course, that we should not share the Faith. Indeed we must! But we must exercise right judgement. Is the person open and receptive to that which we have to offer? The woman in the above passage was. She was humble, and worshiped Jesus, and accepted that she was not worthy of the gift He has to offer. It is this Faith that Jesus rewards.
Jesus knew she had this Faith. He's God, and is capable of reading the hearts of people, which He demonstrated repeatedly throughout His ministry. So, even though He knew her Faith, He still spoke to her in this way. Why? Among other important reasons, He did so to demonstrate how we must exercise this judgement. We must be careful who we offer the holy gift of Jesus and Faith to. If we discern that they will profane God and His grace and turn to harm His holy people, we must refrain from giving them the "bread of the children," in order to protect it. If, however, we discern that there is openness to that gift of God, then we should give it freely, and rejoice in their faith!
One final note. Jesus speaks about two kinds of people here: dogs and swine. I'll offer my interpretation of these two categories. In Jewish kosher laws, swine were considered unclean, and could not be eaten. They were, themselves, unholy creatures. Dogs were not considered as such. Thus, I discern two categories of people: 1) dogs--those who are not of the Faith, but are indifferent to it, and 2) swine--those who are not of the Faith, and who are actively against it, who promote that which is unholy and sacrilegious, and who wish to destroy the Faith. The dogs are those who would profane that which is holy by ignorant disrespect, and the swine are those who would deliberately trample that holy thing into the ground, and then attack those who are of the Faith.
We must be discerning about who we share our Faith with. Share it, but make sure it will be received with due respect.
God bless, and thank you for reading!