Deuteronomy 23:3-6 says:"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:4 Because
they met you not with bread and with water in the way, when ye came
forth out of Egypt; and because they hired against thee Balaam the son
of Beor of Pethor of Mesopotamia, to curse thee. 5 Nevertheless the Lord thy God would not hearken unto Balaam; but the Lord thy God turned the curse into a blessing unto thee, because the Lord thy God loved thee. 6 Thou shalt not seek their peace nor their prosperity all thy days for ever".
The above passage shows how God curse a generation because of their action towards His people (Israelite). God pronounced that no Ammonite or Moabite will enter into His congregation, even to their tenth generation.
Ruth was a Moabites but through her faith-Ruth 1:16-17, caring for her mother in law- Ruth 2:7, not being selfish ( by making sure her mother in law never lack)-Ruth 2:14,17, obedient by not looking down on her mother in law ( Ruth 4:13-17), God enable her to conceive after she has lost everything and of age,.
At this time, Ruth should not less than 45-50 years of age but yet the Almighty God enabled her to conceive and the woman that was condemned, came from a curse generation (Moabites) became the restorer of live-Ruth 4:17
Beloved, not being hospitable is a great offense in the sight of God-Hebrew 13:2, in fact God sees us as someone that is worst than an infidel if we can not provide for our parents etc.-1st Timothy 5:8.
Ruth's action makes God to be committed to bless her-Ruth 2:11-12.
Beloved, how are you threatening your in law, and fellow ones? Do you see them as an enemy or someone that you must love, cherish, be kind and friendly to.
Irrespective of the circumstances, let us always be hospitable and not being hostile to our in laws and fellow ones because whatever we are doing now will surely have a pay back effect.
Shalom!