One of the most inspiring messages of the book of Ruth is that a person who displays selfless compassion will be rewarded in the end. At the beginning of the book, readers are introduced to Naomi and her two daughters-in-law, Ruth and Orpah. After a sequence of tragedies leave all three women as widows, Naomi decides to return to the land of Israel. But Naomi offers to let the young women stay in Moab, their own land. Both women protest, but Orpah eventually concedes and kisses her mother-in-law goodbye. Ruth, however, proclaims her undying loyalty to Naomi, so the two travel to Israel.
Ruth offers to work in the fields as a gleaner to support her mother-in-law and herself. As it turned out, she unwittingly chose the field of Boaz, one of Naomi's close relatives, to work in. Boaz takes notice of her immediately, and after finding out who she is, he praises her for her kindness to Naomi. He says, "May the Lord repay you richly for what you have done. May you be richly rewarded by the Lord, the God of Israel, under whose wings you have come to take refuge."
On Naomi's advice, Ruth presents herself to Boaz for marriage, and he considers her offer a great "kindness" since he is older than she. He goes through the necessary legal maneuvers to claim her as his wife and thereby redeem all Naomi's lost property. The town elders approve the match and shower them with blessings. Those blessings are realized when Ruth bears a son, who later will become the father of King David, putting Ruth, a foreigner, in the genealogical line of Jesus himself.
Ruth's happy ending is due to her loyalty to Naomi, the great kindness she showed her mother-in-law in giving up her own comfort to support her, and the kindness she showed Boaz in seeing past his age and agreeing to take him as her husband. The strong theme that comes through in this book is that kindness will be rewarded.