Ruth lived in the house of Elimelech and learned the ways of the Torah. She was converted only when she joined Naomi and dedicated her soul to God.
“וַתֹּאמֶר רוּת אַל-תִּפְגְּעִי-בִי, לְעָזְבֵךְ לָשׁוּב מֵאַחֲרָיִךְ: כִּי אֶל-אֲשֶׁר תֵּלְכִי אֵלֵךְ, וּבַאֲשֶׁר תָּלִינִי אָלִין–עַמֵּךְ עַמִּי, וֵאלֹהַיִךְ אֱלֹהָי”
“בַּאֲשֶׁר תָּמוּתִי אָמוּת, וְשָׁם אֶקָּבֵר; כֹּה יַעֲשֶׂה יְהוָה לִי, וְכֹה יוֹסִיף–כִּי הַמָּוֶת, יַפְרִיד בֵּינִי וּבֵינֵךְ.”
“But Ruth replied: “Do not urge me to leave you or to turn from following you. For wherever you go, I will go, and wherever you live, I will live; your people will be my people, and your God will be my God.”
“”Where you die, I will die, and there I will be buried. Thus may YHVH do to me, and worse, if anything but death parts you and me.”
“כִּי חֵלֶק יְהֹוָה עַמּוֹ יַעֲקֹב חֶבֶל נַחֲלָתוֹ.”
“For YHVH’S portion is His people; Jacob is the allotment of His line of inheritance.”
The children of Israel connect with a ‘line’ to YHVH.
The Moabites have hurt the Israelites at the time of Moses and even after that. They held to the ‘line’ of Israel and got marked for their negative deeds toward Israel. King David could identify and kill the Moabites that were from the negative seed of those who hurt Israel.
2 Samuel 8:2
“וַיַּךְ אֶת מוֹאָב וַיְמַדְּדֵם בַּחֶבֶל הַשְׁכֵּב אוֹתָם אַרְצָה וַיְמַדֵּד שְׁנֵי חֲבָלִים לְהָמִית וּמְלֹא הַחֶבֶל לְהַחֲיוֹת וַתְּהִי מוֹאָב לְדָוִד לַעֲבָדִים נֹשְׂאֵי מִנְחָה.”
“He defeated Moab, and measured them with the line, making them lie down on the ground; and he measured two lines to put to death and one full line to keep alive. And the Moabites became servants to David, bringing tribute.”
The ‘full line’ was a connection to Malchut that helped King David to tell who to kill and who to keep alive.
Those who hurt the children of Israel are remembered and when the time comes, even after many generations they will be ‘corrected’.