ISB ~ Matthew 7 v6

dogs … swine:Derogatory Jewish epithets for pagans (15:26-28). Dogs were generally undomesticated in Jewish culture, and most were stray scavengers. Swine were especially contemptible to Jews; they were unclean and could not be eaten (Lev 11:7-8; cf. Is 66:3). Jesus redirects these insulting labels to anyone inhospitable to the gospel, Jew or Gentile (cf. Phil 3:2; Rev 22:15).

what is holy:In Judaism, holiness characterized anything consecrated for covenant worship. To treat holy articles in a common manner would profane them (Ex 29:37; Lev 22:10-16). Jesus carries this same notion into the New Covenant. The early Church applied this statement to the Holy Eucharist, a sacrament rightly withheld from the unbaptized (Didache 9:5).