The following is an excerpt from
The MacArthur New Testament Commentary on Matthew 7.
Do not give what is holy to dogs, and do not throw your pearls before swine, lest they trample them under their feet, and turn and tear you to pieces. (Matthew 7:6)
In biblical times dogs were seldom kept as household pets in the way they are today. Except for those used as working animals to herd sheep, they were largely half-wild mongrels that acted as scavengers. They were dirty, greedy, snarling, and often vicious and diseased. They were dangerous and despised.
It would have been unthinkable for a Jew to have thrown to those dogs a piece of holy meat that had been consecrated as a sacrifice in the Temple. Some parts of those offerings were burned up, some parts were eaten by the priests, and some would often be taken home and eaten by the family who made the sacrifice. The part left on the altar was the part which was consecrated exclusively to the Lord, and therefore was holy in a very special way. If no man was to eat that part of the sacrifice, how much less should it be thrown to a bunch of wild, filthy dogs. Such an act would be the height of desecration.
Swine were considered by Jews to be the epitome of uncleanness. That is the reason Antiochus Epiphanes’ sacrifice of a pig on the Jewish altar and forcing the priests to eat it was such an absolute abomination-and touched off the Maccabean revolt against Greece in 168 b.c.
Because a Jew would never have tried to domesticate a pig, most of the swine they encountered were, like the dogs, wild animals who foraged for themselves, often in garbage dumps on the edge of town. Like the scavenging dogs, those swine were greedy, vicious, and filthy even by ordinary pig standards. If you came between them and their food they would likely turn and tear you to pieces with their tusks and sharp hooves.
Jesus’ point is that certain truths and blessings of our faith are not to be shared with people who are totally antagonistic to the things of God. Such people are spiritual dogs and swine, who have no appreciation for that which is holy and righteous. They will take that which is holy, the pearls (the rarest and most valuable of jewels; see Matt. 13:45–46) of God’s Word, as foolishness and as an insult.
A wild animal whose primary concern is scavenging for food will hardly appreciate being thrown a pearl. He will resent its not being something to eat and possibly attack the one who throws it.
Dogs and swine represent those who, because of their great perversity and ungodliness, refuse to have anything to do with the holy and precious things of God except to trample them under their feet, and turn and tear God’s people to pieces.
There will be times when the gospel we present is absolutely rejected and ridiculed and we make the judgment to turn away and speak no more, deciding that we should “shake off the dust of [our] feet” (Matt. 10:14) and begin ministering somewhere else. There will be times when those to whom we witness will resist the gospel and blaspheme God, and we may speak words of judgment. Like Paul, we must then say, in effect, “Your blood be upon your own heads! I am clean. From now on I shall go to the Gentiles” (Acts 18:6). When people not only reject the gospel, but insist on mocking and reviling it, we are not to waste God’s holy Word and the precious pearls of His truth in a futile and frustrating attempt to win them. We are to leave them to the Lord, trusting that somehow His Spirit can penetrate their hearts-as He apparently did with some of those who at first rejected the preaching of Paul and the other apostles-or leaving them to the just judgment of God.