A variety of uses can be observed in ancient Jewish and Christian sources.
- Of pagans or Gentiles (Mark 7:27):
... it isn't good to take bread out of children's mouths, and throw it to the dogs.
- Of Samaritans, (Gen. R. 81.3):
to what are you [Samaritans] compared, to dogs ...
- Of those not baptized (Did 9:5):
Let no-one eat or drink of your thanksgiving [meal]
save those who have been baptized in the name of the Lord,"Do not give what is holy to the dogs."
since the Lord has said concerning this,
- Of Christians who have lapsed (2Pet 2:22):
It has happened to them according to the true proverb:
The dog returns to its vomit,and the scrubbed sow wallows again in the mud.
John Dominic Crossan
Crossan [Historical Jesus] (352 & 364) suggests that this saying does not originate with Jesus. Its strong sense of opposition seems to reflect a context later than the time of Jesus, while the version in the Didache reflects group boundaries based on baptism:
... Didache 9-10 represents a ritualization of the open commensality of Jesus and his first followers. There is nothing necessarily wrong with such a development, but, especially as one follows that worthiness warning from Didache 10:6b into 9:5, it is hard not to acknowledge a loss: the holy ones are now at table, and the dogs are not to be fed.
The commentary in [The Five Gospels] (p. 154f) notes that "dogs and pigs were symbols for whatever is socially and religiously impure." Opinion among the Fellows was divided. Some considered this saying, that seems to condone contemptuous attitudes to others, as inimical to the teachings and practice of Jesus. Others took the saying as reflecting the words of Jesus about choosing an audience likely to see, hear and understand.
Samuel T. Lachs
Lachs [Rabbinic Commentary on the New Testament] (138-140) identifies ancient Jewish parallels and background ideas, including the anti-Samaritan parallel cited above. He notes that the wild boar was used on Roman military banners, and that this saying in Matthew reflects a distinctive Matthean emphasis on sayings attributed to Jesus that have a narrowly Jewish intent.
Luedemann [Jesus] (150) notes that the saying is typical of a proverb whose original reference has become problematic. He cites Did 9:5 as evidence that "already in the first century people no longer understood the saying." Luedemann suggests the saying did not originate with Jesus.
John P. Meier
Meier [Marginal Jew] (I,135) cites this saying as one of several examples from GThom of parallels to exclusively Matthean traditions. He does not consider the origins or the meaning of the saying in the first three volumes of A Marginal Jew.
Muslim Jesus Traditions
Tarif Khalidi [The Muslim Jesus] provides the following traditions relevant to this cluster.
64 Jesus said to the disciples, "O disciples, do not cast pearls before swine, for the swine can do nothing with them. Do not impart wisdom to one who does not desire it, for wisdom is more precious than pearls and whoever rejects wisdom is worse than a swine." [mid-ninth century]
127 Jesus and his disciples passed by a dog's carcass. The disciples said, "How foul is his stench!" Jesus said, "How white are his teeth!" He said this in order to teach them a lesson—namely, to forbid slander.
128 A pig passed by Jesus. Jesus said, "Pass in peace." He was asked, "Spirit of God, how can you say this to a pig?" Jesus said, "I hate to accustom my tongue to evil." [late-ninth century]
Khalidi comments on the double set of sayings:
They both concern animals distasteful to classical Muslim sensibilities. The pig is of course a totally unclean animal, while contact with a dog necessitates ablution according to most Muslim jurists. Both sayings, therefore, are in some sense offensive to Muslim taste, even if neither saying violates Muslim law in a strict sense. (p. 122)
Khalidi also reports the opinion of "the celebrated orientalist Ignaz Goldziher" (cited in Asin 'Patrologia Orientalis', 605) that this saying was of Buddhist origin.
His collection also includes the following:
/200/ Jesus said, "To dispense wisdom to other than those worthy of it is to do an injustice, and to bar it from those worthy of it is to do them an injustice. Be like the gentle physician who applies medication to the place of illness." In another version, he said, "He who dispenses wisdom to other than those worthy of it is ignorant, and he who bars it from those worthy of it has done an injustice. Wisdom has its due, and it has people who are worthy of it, so give every man his due." [early twelfth century]