Genesis 43:31-34

32. Because the Egyptians might not eat, etc Moses says they might not eat with the Hebrews, because they abhorred it, as being unlawful. For seeing that their religion forbade it, they were so bound, that they could not do what they did not dare to do. This passage teaches us how great was the pride of that nation; for, whence did it arise that they so utterly detested the Hebrews, unless because they thought themselves alone to be pure and holy in the world, and acceptable to God? God, indeed, commands his worshipers to abstain from all the pollutions of the Gentiles. But it behoves any one who separates himself from others, to be himself pure and upright. Therefore superstitious persons vainly attempt to claim this privilege for themselves, seeing they carry their impurity within, and are destitute of sincerity. Superstition, also, is affected with another disease; namely, that it is full of pride, so that it despises all men, under the pretext that they are vicious. It is asked, however, whether the Egyptians were separated from Joseph, because they regarded him as polluted: for this the words of Moses seem to intimate. If this interpretation is received, then they esteemed their false religion so highly, that they did not scruple to load their governor with reproaches. I rather conjecture, that Joseph sat apart from them, for the sake of honor; since it would be absurd that they, who disdained to sit at the same table with him, should be invited as his guests. Therefore it is probable that this distinct order was made by Joseph himself, that he might maintain his own dignity; and yet that the sons of Jacob were not mixed with the Egyptians, because the former were an abomination to the latter. For though the origin of Joseph was known, yet he had so passed over to the Egyptians, that he had become as one of their body. For which reason, also, the king had given him a name, when he adorned him with the insignia of his office as chief governor. Now, when we see that the church of God was, at that time, so proudly despised by profane men, we need not wonder that we also, at the present day, are subjected to similar reproach. Meanwhile, we must endeavor to keep ourselves pure from the filth of the world, for the Lord’s sake; and yet this desire must be so at tempered, that we may be alienated from the vices, rather than from the persons of men. For on this account does God sanctify his children, that they may beware of the vices of the unbelievers among whom they are conversant; and nevertheless may allure, as many as are curable, to a participation of their piety. Two things are here to be attended to; first, that we may be fully persuaded of the genuineness of our faith; secondly, that our excessive and fruitless fastidiousness may not entirely alienate many from the Lord, who otherwise might have been won. For we are not expressly commanded so to abhor the wicked, as not eat with them; but to avoid such association as may subject us to the same yoke. Besides, this passage confirms what I have before said, that the Hebrews had derived their name, not from their passing over the river; (as some falsely imagine,) but from their ancestor Heber. Nor was the fame of a single small and distantly situated family, sufficiently celebrated in Egypt, to become the cause of public dissension.