Answer
Deuteronomy 23:3–6 says, “No Ammonite or Moabite or any of their descendants may enter the assembly of the Lord, not even in the tenth generation. For they did not come to meet you with bread and water on your way when you came out of Egypt, and they hired Balaam son of Beor from Pethor in Aram Naharaim to pronounce a curse on you. However, the Lord your God would not listen to Balaam but turned the curse into a blessing for you, because the Lord your God loves you. Do not seek a treaty of friendship with them as long as you live.” But then we read later that Boaz, a Jew living in Bethlehem, married Ruth, a Moabitess (Ruth 4:13). How was Boaz and Ruth’s marriage not a violation of God’s law?
Other commands in the Mosaic Law forbade the Israelites from marrying the Canaanites (e.g., Deuteronomy 7:1–6). Moab was not a Canaanite nation, and so those laws did not apply to Ruth and Boaz. However, Deuteronomy 23:3 specifically mentions Moabites as ineligible for admittance into the assembly of the Lord. It’s this law that raises the difficulty for Ruth.
There are several factors that make the marriage of Boaz and Ruth acceptable, even though Ruth was a Moabitess:
1) The wording of the law in Deuteronomy 23:3 forbids only the naturalization of Ammonites and Moabites. It says nothing about their dwelling in the land of Israel, and it does not explicitly mention marriage.
2) According to Jewish law and tradition, curses follow the father, not the mother. In Jewish commentaries, rabbis generally interpreted the command of Deuteronomy 23:3 to apply to a (male) Moabite, but not to a Moabitess: “Ammonite and Moabite converts are prohibited from entering into the congregation and marrying a woman who was born Jewish, and their prohibition is eternal, for all generations. However, their female counterparts, even the convert herself, are permitted immediately” (Misnah Yevamot 8:3).
3) Ruth was a proselyte to the Jewish religion. Her words to her mother-in-law, Naomi, indicate her devotion not only to Naomi but to the God of Israel: “Where you go I will go, and where you stay I will stay. Your people will be my people and your God my God” (Ruth 1:16).
4) God blessed the marriage of Ruth and Boaz and used the union to further His plan to bless Israel (Ruth 4:13–22).
Many people mistake God’s prohibition of the Israelites’ intermarrying with other nations for a denunciation of those races or ethnicities. But such commands were not meant to raise a racial/ethnic issue. At the core was a religious issue. God did not want the Israelites marrying people who worshiped false gods, and the reason was obvious: “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 children away from following me to serve other gods, and the Lord’s anger will burn against you and will quickly destroy you” (Deuteronomy 7:3–4).
King Solomon foolishly ignored God’s law and married women from pagan cultures. The result was just as God had predicted: “His wives led him astray. As Solomon grew old, his wives turned his heart after other gods, and his heart was not fully devoted to the Lord his God” (1 Kings 11:3–4). Boaz married a woman from a pagan culture, but she did not bring her worship of Chemoth to Israel with her. Rather, she devoted herself to the One True God. Doing so made her no longer a Moabitess, at least in the religious sense. And Ruth found that she was accepted by Him who “does not show favoritism but accepts from every nation the one who fears him and does what is right” (Acts 10:34–35).
