Shavuot, which falls this year on 19 May, celebrates the giving of the Torah on Mount Sinai. It is also one of the three Pilgrimage festivals: in Temple times, people would bring offerings from the wheat harvest to the Temple in Jerusalem.
The traditional reading for Shavuot is the Book of Ruth. The Book tells how Naomi’s husband and sons die while living in the land of Moab. She decides to return to Bethlehem, and entreats her Moabite daughters-in-law to go back to their mothers’ houses. One daughter-in-law, Orpah, goes. But Ruth refuses, in one of the most beautiful passages of the Hebrew Bible:
‘Entreat me not to leave thee, and to return from following after thee; for whither thou goest, I will go; and where thou lodgest, I will lodge; thy people shall be my people, and thy God my God; where thou diest, will I die, and there will I be buried; the LORD do so to me, and more also, if aught but death part thee and me.’ [Ruth 1:16-7]
When Naomi returns to Bethlehem with Ruth, they are very poor. Naomi’s kinsman Boaz allows Ruth to glean in his field and eat with his workers, gathering up the fallen corn. Naomi urges Ruth to lie by Boaz’s feet at the threshing floor. The next day Boaz marries Ruth.
There is no one reason why we read the Book of Ruth at Shavuot. On first reading, it’s not even clear why this story is included in the Hebrew Bible. A story about a foreign woman, with no mention of laws or prophecies, no miracles or acts of G-d? In the Midrash, we see this explanation:
‘This scroll contains no reference to pure or impure or to forbidden or permitted. Why, then, was it written? To teach you how profitable is the reward for those who perform kindness.’
The Book of Ruth is replete with acts of human kindness. Ruth stays with Naomi through her hardships, and, ultimately, bears a son for her. Boaz feeds Ruth and tells his workers to leave barley for her. ‘Thou hast shown more kindness,’ says Boaz, when Ruth comes to him on the threshing floor. By choosing Boaz over a younger man, and thereby providing a son for Naomi, Ruth is kind both to him to Naomi.
Ruth is often regarded as the first convert to Judaism, and her acceptance of the Torah parallels the Jewish people’s acceptance of the Torah at Shavuot. Her great-grandson, King David, is said to have died on Shavuot. The messiah will be a descendant of King David, and thus of Ruth.
The entire Torah, said the great sage Rabbi Hillel, is ‘that which is hateful to you do not do to another’ – the rest is commentary. It is fitting, then, that we commemorate the giving of the Torah by reading about kindness. It is from Ruth – a destitute refugee woman, a foreigner – and the compassion shown to her by others, along with her own many acts of kindness, that the Messiah will come and fulfil the promises of the Torah.
 Midrash Ruth Rabbah 2:15