The story of Ruth we read about in the Bible, in the book that bears her name. The story takes place during the times of the Judges, approx. BC 1336. This was known to be a time of religious and moral degeneracy.
The story begins when Elimelech and his wife Naomi and their two sons travelled to Moab to live, because there was a famine in their land of Bethlehem in Judah. Elimelech dies soon after. Naomi's two sons marry Moabite women, Orphah and Ruth. After 10 years both sons died. Naomi decides to leave Moab and journey home to Judah as she had heard that the famine was over. She told her 2 daughters in law to return to the house of their mother’s, (obviously women at this time had no way of earning their own living), there is no mention of any children being born to Orpah or Ruth.
Orpah returns to her own home, but Ruth stayed with Naomi saying in Chapter 1 vs. 16-18, "Intreat me not to leave thee, or 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 ought but death part thee and me".
We see here, at this stage in Ruth's life that she has left the pagan gods of her own family and desired to follow after the true God, the God of Israel. She shows by these words how much she loves Naomi and her reverence for the God of Israel, and her trust in Him whatever His will for her, is apparent. Whereas Orpah returned to her mother's home and her people’s gods. On their return to Bethlehem, Naomi makes it clear that she feels the Almighty has dealt harshly with her.
In Chapter 2 we are shown that Naomi's husband had a relative in Judah whose name was Boaz (meaning, in him is strength), he was a wealthy man. Ruth asked Naomi if she could go into the field as the harvest is taking place, to collect grain from the borders of the field. This was a Jewish law, where some grain would be left around the borders of the fields for the poor to collect, see Lev. 19:9-10, 23:22, and Deut. 24:19. Ruth was clearly aware of the Jewish law and was eager to provide for herself and Naomi. She arrived in the field belonging to Boaz, and when he saw her he enquired who she is. On hearing about her character he approached her and complements her on her kindness to Naomi. He told her to collect as much grain as she liked and provided refreshment for her. He also asked the God of Israel to reward her for her trust in Him.
On her return home she told Naomi whom she had met, and was told that he was a relative of her father in law. Ruth continues to collect grain in Boaz's field until the end of the harvest. (Therefore near the feast of Pentecost). [This is why the book of Ruth is read at the Jewish feast of Pentecost to this day].
Chapter 3 shows how Naomi encourages Ruth to claim the Levirate law (or Kinsman Redeemer Law), Deut. 25:5-10. [This law instructed the care of a young widow. An immediate relative who was willing, was to marry her and raise children by her to keep the family name. Also land and goods were to be bought by the relative and cared for so they did not go out of the family]. Naomi instructed Ruth to go to Boaz in the evening after the harvest, and lie at his feet. In the night when Boaz found her lying at his feet he asked in v.9 "who art thou"? she replied "I am Ruth thine handmaid; spread therefore thy skirt over thine handmaid; for thou art a near Kinsman". (This is symbolic of her request of him to look after her and to marry her which is her right to request under the Jewish, Kinsman Redeemer Law).
However, in Chapter 4 it is clear that Boaz knew there was another man who was a closer relative to Naomi, whose right it was to fulfill the Kinsman Redeemer Law, therefore Boaz asked him if he was prepared to fulfill this law.
There also appears to be a piece of land owned by Naomi which is part of the proposed transaction. On hearing this he declines the offer, and Boaz, in front of the 10 witnesses he had called together from the town, purchased the property of Elimelech and all that was Chillon's and Mahlon's, and takes Ruth to be his wife.
The God of Israel blessed their union and soon Ruth has a son, and they call him Obed, (the name means man's servant, possibly the servant of the Lord). The women of the town are full of joy for Naomi, and praise the God of Israel for his goodness to her, saying she is no longer empty, but has become full, (this was symbolic of how Bethlehem had been empty i.e. a draught being the cause of Naomi's family leaving in the first place, to the return to Bethlehem at the time of the harvest, leading to a time of fullness in the land).
The women also say that Ruth had been better to Naomi than 7 sons, (7 in the Jewish tradition means completeness, and having 7 sons was the epitome of all family blessings in Israel). [This throws particular light on why the Sadducees in Matt. 22:24-30, asked Christ about the 7 brothers, all dying after marrying the same woman. We see here again how they used the Jewish tradition in a perverse way to seek to trick Christ, see: Seven Husbands ]. Ruth's selfless devotion to Naomi receives its climatic acknowledgement here in this complement.
Obed became the father of Jesse, who became the father of king David. During his time as king, in contrast to the turbulent period of the Judges, Israel had a time of rest in the 'Promised Land'. It signified, as Naomi was brought from emptiness to fullness through the selfless love of Ruth and Boaz, so Jehovah brought Israel from unrest to rest through their descendant David, who selflessly gave himself to fight Israel's battles on Jehovah's behalf. The ultimate end will be when their Messiah Christ Jesus, (great David's greater Son; 2Sam. 4-17, Isa. 7:13-14, Mark 12:35-37 and Luke 1:32) who fulfils prophecy will bring Israel into final Earthly rest for a 1000 years. During this period of time the Jews will be the Kingdom of Priests and the Nation they should have been earlier! Also the whole Earth will be blessed through them at that time.
Summary: Ruth's complete loyalty to an Israelite family into which she had been received by marriage, and her total devotion to her desolate mother in law, showed the kind of woman she was. Ruth exemplifies that the participation into God's favour is not dependent on blood or birth, (as she was a Moabite, these were the descendants of the union of Lot and his eldest daughter, therefore she was a Gentile), but by "obedience that comes from faith, Rom. 1-5". She became the great grandmother of King David and therefore an ancestor of Jesus the Christ.