Ruth 4:17 marks the first time in the English Bible that David, son of Jesse and future King of Israel, is mentioned. The events in the book of Ruth took place several decades prior to David’s birth (Ruth 1:1), but the great-grandson of Ruth is mentioned twice at the end of the book (4:17,22) in order to highlight the lineage of the Messiah—from Judah’s son, Perez (Ruth 4:18; Genesis 38:29; cf. 49:10), to Obed (Ruth's son), to David (to whom God promised an heir, Who would establish an eternal kingdom—2 Samuel 7:12-13; Psalm 89:3-4; Luke 31-33).
Many skeptics question how David could be a descendant of Ruth, a Moabite, and yet also become the divinely chosen King of Israel (1 Samuel 16:1-13). After all, Moses wrote: “An Ammonite or Moabite shall not enter the assembly of the Lord; even to the tenth generation none of his descendants shall enter the assembly of the Lord forever” (Deuteronomy 23:3). So how could King David, the great-grandson of a Moabite woman, be allowed into the assembly of God?
First, one must consider the meaning of the phrase “shall not enter the assembly of the Lord.” Did Moses mean that Ammonites or Moabites (1) could not live within the borders of Israel, (2) could not become part of the Israelite community in general, (3) could not gather together and become part of an actual assembly of the Israelites (cf. Deuteronomy 5:22; 9:10; 10:4; 18:16), (4) could not become one of the elders or officials who often assembled together (cf. Deuteronomy 31:28,30), and/or (5) could not become part of the religious community (cf. Leviticus 21:17-21)—that is, were they forbidden “from participation in religious rites in the homes and at the tabernacle and later at the temple”1? While Moses and the original recipients of this command doubtlessly understood the precise meaning of Deuteronomy 23:3, those living 3,500 years this side of the giving of the Law of Moses (and who have never been accountable to that law), may never know for sure exactly what the Lord meant. And, if neither the Christian nor the skeptic can know for sure what the precise meaning of the “assembly of the Lord” is in Deuteronomy 23:3, then obviously no proven contradiction exists.
Second, different kinds of “outsiders” lived in and around the Israelites. With two-and-one-half tribes of Israel inhabiting the east side of the Jordan (Numbers 32), where the Moabites and Ammonites lived and where the Israelites were currently camping (Deuteronomy 1:5; 29:1) when Moses gave the Moabite/Ammonite restriction of Deuteronomy 23:3, he was referring to the non-converted, uncircumcised “alien” or “foreign” Moabite/Ammonite who was never to be allowed into the general Israelite community. Ruth may have been a Moabite ethnically, but religiously she was a dedicated follower of the LORD (Ruth 1:16-18), who participated in and abided by Mosaic law (Ruth 3:1-18; 4:1-12; Deuteronomy 25:5-10).2 Thus, she and her faithful descendants (including David) were rightly accepted in Israel.
Another reason Deuteronomy 23:3 would not have applied to Ruth and her offspring is simply because a non-Israelite mother in Israel (especially one who was a proselyte!) did not determine the nationality of her offspring. Joseph’s Egyptian wife did not make their sons Ephraim and Manasseh Egyptians (Genesis 41:50-52). Moses’ marriage to Zipporah, a Midianite (Exodus 2:11-25), did not disqualify their sons Gershom and Eliezer from being Israelites (Exodus 2:22; 18:1-4), nor did it make them Midianites. Salmon’s marriage to Rahab (the Jerichoan harlot) did not mean their son Boaz was a recognized Gentile of Jericho (Matthew 1:5). And the Moabitess Ruth, wife of Boaz, did not make their son Obed, their grandson Jesse, their great-grandson David, or their descendants Joseph and Mary (the earthly parents of Jesus) anything other than legitimate descendants of Abraham (Matthew 1:1-17; Luke 3:23-38)—according to the standard reckoning of Israelite heritage. In the eyes of all of Israel, David was an Israelite of the tribe of Judah—and was no more a Moabite than he was a Jerichoan.3
Although Boaz, Ruth, and David were imperfect people (Romans 3:23), who broke various Old Testament commandments (cf. Samuel 11-12), neither these three nor God (in appointing David as king over Israel) ignored or broke the law of Deuteronomy 23:3.
1 Earl Kalland (1992), The Expositor’s Bible Commentary: Deuteronomy (Grand Rapids, MI: Zondervan), 3:140.
2 Some think that Nehemiah 13:1,25,27 contradicts this explanation of Ruth and Deuteronomy 23:3. The social situation in Ezra and Nehemiah’s day (approximately 600 years after the time of Ruth), however, was quite different than what is found in the book of Ruth. Many of the Jews who had returned from 70 years of Babylonian captivity had taken for themselves “pagan” wives from among the Moabites, Ammonites, etc. (Ezra 9:1-2,14; 10:2,10-18,44; Nehemiah 13:23-30), rather than enter into lawful marriages with Jews or faithful converts to Judaism. The Old Testament prohibitions of marrying foreigners (Exodus 34:15-16; Deuteronomy 7:1-4) applied to pagan non-converts, not faithful proselytes.
3 He was the great-great-grandson of Rahab of Jericho, but David was not Jerichoan.