And he said unto them,.... The whole company that were met together, who were chiefly, if not altogether Gentiles:ye know that it is an unlawful thing; what is forbidden by the law of Moses, De 7:2 and by the traditions of the elders, which carry the matter further than the law did, and made it very criminal:for a man that is a Jew, to keep company with, or come unto one of another nation; besides entering into covenants and marriages with them, which were forbidden by the law, though they allowed of trade and commerce with the Gentiles, yet not any familiar conversation with them; it was prohibited to eat and drink any sort of liquor with them in their houses , nor might they walk with them in the streets, or on the road; says Maimonides ,"it is forbidden a Jew to unite himself to Gentiles, because they are suspected of shedding blood, and he may not join himself with them in the way; if he meets a Gentile in the way, he causes him to turn to the right hand; if they ascend by an ascent, or descend by a descent, the Israelite may not be below, and the Gentile above: but the Israelite must be above, and the Gentile below, lest he should fall upon him and kill him; and he may not go even with (or along side by him) lest he break his skull.'
'It is said of some Rabbins, that they saw a certain man coming;"says R. Chiyah, let us be gone, perhaps this man is an idolatrous Gentile, or one of the people of the earth, and it is forbidden to join with him in the way.'
'They looked upon the houses of Gentiles unclean, and therefore would not enter into them: See Gill on "Joh 18:28".yea they say , that:"the court of a stranger (or Gentile) is as the habitation of a beast.'
'Such an aversion was there in that people to all civil society with Gentiles: and so Apoltonius says of them , that"they not only departed from the Romans, but from all men, living a separate life from others; nor did they communicate at table with others; neither in things sacred, nor in any ceremonies;''and this was well known to Jews and Gentiles:but God hath showed me; partly by the vision he had seen, and partly by discourse with the men that came from Cornelius to him; and by comparing the vision and their message to him together, he saw that he was not obliged to abide by the customs and laws of the Jews: but was showed, as he says,that I should not call any man common or unclean; that is, in a ceremonial sense; for otherwise, all by nature are morally unclean; and none are pure, but such who are washed in the blood of Christ, and are justified by his righteousness, and sanctified by his Spirit: he saw there was now no difference between Jew and Gentile; that the one was not clean because of his circumcision, nor the other unclean on account of his uncircumcision, or to be avoided for that reason; that the Gospel was to be preached to all; and that every believer of whatsoever nation, was acceptable to God, and ought to be regarded by his ministers and people.
Mitzvot Tora, pr neg. 143. Hilchot Rotzeach, c. 12. sect. 7. Zohar in Exod. fol. 21. 1. T. Bab. Erubin, fol. 62. 2. Philostrat. Vita Apollon. l. 5. c.