Updated: Oct 22, 2020
One of the puzzles that confront Bible students is what to do with the prohibition against Moabites in the Word of God. 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, Deuteronomy 23:3. In three more books Ruth will be allowed into the congregation and she is clearly from Moab.
There is a strain within fundamentalism that attempts to allow David to escape this curse by counting him as the tenth generation. By this reasoning Obed was the first generation to come from Ruth, Jesse was the second. Then a slight of hand is used. This theory then counts each of Jesse's sons as a generation in their own right. Since David is the seventh son, by this reckoning he would be accounted the tenth generation.
I once discussed this with a very religious Jew who took his bible quite seriously. He was horrified by the liberty taken in ascribing each of Jesse's son's as a generation. What advantage then hath the Jew? or what profit is there of circumcision? Much every way: chiefly, because that unto them were committed the oracles of God, Romans 3:1,2. When I talked with this Jew unto whom God had committed the oracles of God he proposed a rather simple solution. He read the scriptures in Hebrew and in Hebrew only the male Moabite was banned from ever entering the congregation. There was no prohibition on the females.
Anyone who knows my stand on scripture knows that I immediately bristle when people try to prove doctrine by going back to the original languages. If it is important, the King James Bible will say it in English. Sure enough, the King James Bible also makes the exact same distinction as the Hebrew. Ruth is never called a Moabite. She is named 13 times in the bible and in five of them she is called Ruth the Moabitess, not Ruth the Moabite. The scriptures do not forbid the Moabite and the Moabitess from entering the congregation, only the Moabite. Your King James Bible is exact.
As for the parlor trick of trying to make David a tenth generation by accounting each of his brothers a generation; it won't fly. The Book of Matthew shoots it down. Matthew 1:17 is very clear that from Abraham to David there are 14 generations. That leaves no room for shenanigans in making extra generations between Ruth and David. Instead learning to take a King James Bible literally will always make things clear.