Definition and Context:
Intermarriage, in the biblical context, refers to the marriage between Israelites and people from surrounding nations who did not worship Yahweh, the God of Israel. The prohibition against such unions is rooted in the concern for religious purity and the potential for leading the Israelites away from their covenantal relationship with God.

Biblical References:

1. Deuteronomy 7:3-4 : "Do not intermarry with them. Do not give your daughters to their sons or take their daughters for your sons, for they will turn your sons away from following Me to serve other gods. Then the anger of the LORD will burn against you, and He will swiftly destroy you."

This passage highlights the primary concern of intermarriage: the risk of leading the Israelites into idolatry. The command is part of a broader set of instructions given to the Israelites as they prepared to enter the Promised Land, emphasizing the need to remain distinct and faithful to God.

2. Exodus 34:15-16 : "Do not make a covenant with the inhabitants of the land, lest they prostitute themselves with their gods and sacrifice to them, and invite you, and you eat of their sacrifices. And when you take some of their daughters as brides for your sons, their daughters will prostitute themselves with their gods and cause your sons to do the same."

Here, the prohibition is linked to the danger of forming covenants with pagan nations, which could lead to participation in their religious practices. The metaphor of prostitution underscores the severity of spiritual unfaithfulness.

3. Ezra 9:1-2 : "After these things had been done, the leaders came to me and said, 'The people of Israel, including the priests and Levites, have not kept themselves separate from the peoples of the lands with their abominations... Indeed, the hands of the leaders and officials have been foremost in this unfaithfulness.'"

In the post-exilic period, Ezra confronts the issue of intermarriage as a significant problem among the returned exiles. The leaders' involvement in such unions is seen as a serious breach of covenant faithfulness.

4. Nehemiah 13:23-27 : "In those days I also saw Jews who had married women from Ashdod, Ammon, and Moab... So I rebuked them and cursed them. I beat some of their men and pulled out their hair. Then I made them take an oath before God: 'You must not give your daughters in marriage to their sons or take their daughters as wives for your sons or for yourselves.'"

Nehemiah's response to intermarriage is one of strong corrective action, emphasizing the importance of maintaining the community's distinct identity and faithfulness to God.

Theological Implications:

The prohibition against intermarriage is deeply tied to the concept of holiness and the call for Israel to be a "kingdom of priests and a holy nation" (Exodus 19:6). The concern is not ethnic purity but religious fidelity. The surrounding nations worshiped multiple gods, and intermarriage posed a threat of syncretism, diluting the worship of Yahweh with pagan practices.

Historical and Cultural Considerations:

In the ancient Near Eastern context, marriage often served as a means of forming political alliances and securing peace between nations. For Israel, however, such alliances through marriage were seen as compromising their unique relationship with God. The biblical narrative consistently portrays intermarriage with foreign nations as leading to negative consequences, such as the introduction of idolatry and moral decline.

New Testament Perspective:

While the New Testament does not explicitly reiterate the Old Testament prohibition against intermarriage, it emphasizes the importance of shared faith in marriage. In 2 Corinthians 6:14 , Paul advises believers, "Do not be unequally yoked with unbelievers," which can be understood as a principle guiding Christian marriage to ensure spiritual unity.

Conclusion:

The biblical injunction against intermarriage serves as a reminder of the importance of maintaining religious integrity and the dangers of compromising one's faith through intimate relationships with those who do not share the same commitment to God.