It seems that Ruth had come to know about Jehovah God, perhaps from her late husband or from Naomi.
يَبْدُو أَنَّ رَاعُوثَ تَعَلَّمَتْ عَنْ يَهْوَهَ مِنْ خِلَالِ زَوْجِهَا ٱلرَّاحِلِ أَوْ حَمَاتِهَا نُعْمِي .‏