Do not give dogs what is sacred; do not throw your pearls to pigs. If you do, they may trample them under their feet, and turn and tear you to pieces.
Matthew Henry
This may be considered, either,
(1) ... A rule to the disciples in preaching the gospel; not that they must not preach it to anyone who were wicked and profane ... but the reference is to such as they found obstinate after the gospel was preached to them, such as blasphemed it and persecuted the preachers of it; let them not spend much time among such, for it would be lost labour, but let them turn to others, Acts 13:41 ...
(2) ... A rule to all in giving reproof. Our zeal against sin must be guided by discretion and we must not go about to give instructions, counsels and rebukes, much less comforts, to hardened scorners, to whom it will certainly do no good, but who will be exasperated and enraged at us. Throw a pearl to a swine, and he will resent it, as if you threw a stone at him; reproofs will be called reproaches, as they were (Lk 11:45; Jer 6:10), therefore give not to ... unclean creatures holy things. ...
[1] Good counsel and reproof are a holy thing, ... a pearl: ... ordinances of God ... precious ...
[2] Among the generation of the wicked, there are some that have arrived at such a pitch of wickedness, that they are looked upon as dogs and swine; they are impudently and notoriously vile ...
[3] Reproofs of instruction are ill bestowed upon such, and expose the reprover to all the contempt and mischief that may be expected from dogs and swine ...
[4] Our Lord Jesus is very tender of the safety of his people, and would not have them needlessly to expose themselves to the fury of those that will turn again and rend them ....
John Gill
Give not that which is holy, etc .... Dogs were unclean creatures by the law; the price of one might not be brought into the house of the Lord, for a vow, Dt 23:18, yea, these creatures were not admitted into several temples of the Heathens. Things profane and unclean, as flesh torn by beasts, were ordered to be given to them, Ex 22:31, but nothing that was holy was to be given them, as holy flesh, or the holy oblations, or anything that was consecrated to holy uses; to which is the allusion here. It is a common maxim with the Jews, ... "that they do not redeem holy things, to give to the dogs to eat".
Here the phrase is used in a metaphorical sense; and is generally understood of not delivering or communicating the holy word of God and the truths of the gospel, comparable to pearls, or the ordinances of it, to persons notoriously vile and sinful: to ... violent and furious persecutors ... impudent blasphemers ... "dogs"; or to such, who are scandalously vile, impure in their lives and conversations, ... swine;
neither cast ye, etc But since the subject Christ is upon is reproof, it seems rather to be the design of these expressions, that men should be cautious and prudent, in rebuking and admonishing such persons for their sins, in whom there is no appearance or hope of success; yea, where there is danger of sustaining loss;
lest they trample them, etc that is, despise the admonitions and reproofs given, and hurt the persons who give them, either by words or deeds; see Prov 9:7. The Jews have ... sayings ... like these ... eg "do not cast pearls before swine, nor deliver wisdom to him, who knows not the excellency of it; for wisdom is better than pearls, and he that does not seek after it, is worse than a swine.''
