An Ammonite or Moabite shall not enter into the congregation of the LORD; even to their tenth generation shall they not enter into the congregation of the LORD for ever: An Ammonite or Moabite - These nations were subjected for their impiety and wickedness, (see Deuteronomy 23:4 and Deuteronomy 23:5), to peculiar disgrace, and on this account were not permitted to hold any office among the Israelites. But this did not disqualify them from being proselytes: Ruth, who was a Moabitess, was married to Boaz, and she became one of the progenitors of our Lord.
Even to their tenth generation - That is, for ever, as the next clause explains; see Nehemiah 13:1.