Intermarriage with unbelieving foreigners was strictly forbidden to Israel (Exodus 34:11–16; Deuteronomy 7:1–4). The reason for this was not ethnicity but religion. By marrying people who do not worship the Lord, the hearts of God’s people would be turned toward serving other gods. However, if a pagan man or woman decided to submit to the Lord and serve him, it seems as if marriage would be permissible (see Ruth). Sadly the history of Israel would show that they refused to submit to this commandment. Indeed, the problem of mixing with nations quickly arose (Judges 2:10–19) and would eventually result in expulsion from the land, being the cause of northern and southern exile (2 Kings 17:7–23; 2 Kings 21:1–26; 2 Kings 24:3–4). It would be a problem even in the post-exilic period (Ezra 9:1–2; Nehemiah 13:23–27).1
12 For if you turn back and cling to the remnant of these nations remaining among you and make marriages with them, so that you associate with them and they with you,