She followed her sister-in- law I think because both her and her sister-in-law's husbands died. Their tradition was that if your husband dies, you go back to your family to be taken care of. Instead of Ruth parting ways, they stayed together and found a farmer that took care of Ruth and her sister-in-law. Ending up Ruth married the farmer. God awarded Ruth by making her a descendant of Jesus. She is a important figure in the Jewish culture.