Deuteronomy 7:3
2-6. thou shalt smite them, and utterly destroy them; thou shalt make no covenant with them—This relentless doom of extermination which God denounced against those tribes of Canaan cannot be reconciled with the attributes of the divine character, except on the assumption that their gross idolatry and enormous wickedness left no reasonable hope of their repentance and amendment. If they were to be swept away like the antediluvians or the people of Sodom and Gomorrah, as incorrigible sinners who had filled up the measure of their iniquities, it mattered not to them in what way the judgment was inflicted; and God, as the Sovereign Disposer, had a right to employ any instruments that pleased Him for executing His judgments. Some think that they were to be exterminated as unprincipled usurpers of a country which God had assigned to the posterity of Eber and which had been occupied ages before by wandering shepherds of that race, till, on the migration of Jacob's family into Egypt through the pressure of famine, the Canaanites overspread the whole land, though they had no legitimate claim to it, and endeavored to retain possession of it by force. In this view their expulsion was just and proper. The strict prohibition against contracting any alliances with such infamous idolaters was a prudential rule, founded on the experience that "evil communications corrupt good manners" [1Co 15:33], and its importance or necessity was attested by the unhappy examples of Solomon and others in the subsequent history of Israel.
Deuteronomy 23:3
3. even to the their tenth generation shall they not enter—Many eminent writers think that this law of exclusion was applicable only to males; at all events that a definite is used for an indefinite number (Ne 13:1; Ru 4:10; 2Ki 10:2). Many of the Israelites being established on the east side of Jordan in the immediate neighborhood of those people, God raised this partition wall between them to prevent the consequences of evil communications. More favor was to be shown to Edomites and Egyptians—to the former from their near relationship to Israel; and to the latter, from their early hospitalities to the family of Jacob, as well as the many acts of kindness rendered them by private Egyptians at the Exodus (Ex 12:36). The grandchildren of Edomite or Egyptian proselytes were declared admissible to the full rights of citizenship as native Israelites; and by this remarkable provision, God taught His people a practical lesson of generosity and gratitude for special deeds of kindness, to the forgetfulness of all the persecution and ill services sustained from those two nations.
Ezra 9:2
1, 2. Now when these things were done—The first days after Ezra's arrival in Jerusalem were occupied in executing the different trusts committed to him. The nature and design of the office with which the royal authority had invested him was publicly made known to his own people by the formal delivery of the contribution and the sacred vessels brought from Babylon to the priests to be deposited in the temple. Then his credentials were privately presented to the provincial governors; and by this prudent, orderly proceeding he put himself in the best position to avail himself of all the advantages guaranteed him by the king. On a superficial view everything contributed to gratify his patriotic feelings in the apparently flourishing state of the church and country. But a further acquaintance discovered the existence of great corruptions, which demanded immediate correction. One was particularly brought under his notice as being the source and origin of all others; namely, a serious abuse that was practised respecting the law of marriage.
the princes came to me, saying—The information they lodged with Ezra was to the effect that numbers of the people, in violation of the divine law (De 7:2, 3), had contracted marriages with Gentile women, and that the guilt of the disorderly practice, far from being confined to the lower classes, was shared in by several of the priests and Levites, as well as of the leading men in the country. This great irregularity would inevitably bring many evils in its train; it would encourage and increase idolatry, as well as break down the barriers of distinction which, for important purposes, God had raised between the Israelites and all other people. Ezra foresaw these dangerous consequences, but was overwhelmed with a sense of the difficulty of correcting the evil, when matrimonial alliances had been formed, families had been reared, affections engaged, and important interests established.