1. The exclusion of foreigners 13:1-3

Discovery of the law that no Ammonite or Moabite should ever receive citizenship in Israel (Deut. 23:3-4) led the leaders to exclude all foreigners from the restoration community.

There are two explanations for Ruth's inclusion. The better one, I believe, is that unbelieving immigrants from these nations were those denied citizenship. This would explain why Rahab, a Canaanite, and Ruth, a Moabite, became citizens. They were both believers. Another explanation is that the use of the Hebrew masculine nouns, Ammonite and Moabite, refer to males exclusively.