Several aspects of this passage are worthy of note. First, the Lord actively causes Ruth to conceive a child, the only time in the book that God is said to act directly. Ruth had been married to Mahlon for ten long years in Moab without conceiving a child. As in so many of the matriarchal and patriarchal stories in Genesis (16; 20-21; 25:19-26; 29:31-30:24), the Lord decides when and to whom a child will be born.
Second, the women of Bethlehem recognize that the Lord is to be blessed for this birth. And third, they recognize more than this; they understand that this child will be the "go'el," the next of kin, the redeemer, thus pointing forward to the birth of a more significant redeemer child in Bethlehem. The women understand that Naomi, who came back bereft from Moab, is now to be restored and nourished by this grandchild. And then, most remarkably, the women say the very opposite of what many would expect they would say about the worth of the child and the worth of Ruth, his mother. Many readers would expect that Ruth, the poor childless Moabite widow, would be considered worthless until she had a child. We imagine that having a son would make her more worthy. But the women say the reverse. They declare to Naomi that the child is made worthy by the mother. Because Ruth loves Naomi, she is said to be more to Naomi than seven sons! Ruth's love and loyalty to Naomi is the reality that makes this new child so dear to Naomi.
13 So Boaz took Ruth and she became his wife. When they came together, the Lord made her conceive, and she bore a son. 14Then the women said to Naomi, Blessed be the Lord, who has not left you this day without next-of-kin;* and may his name be renowned in Israel! 15He shall be to you a restorer of life and a nourisher of your old age; for your daughter-in-law who loves you, who is more to you than seven sons, has borne him. 16Then Naomi took the child and laid him in her bosom, and became his nurse. 17The women of the neighbourhood gave him a name, saying, A son has been born to Naomi. They named him Obed; he became the father of Jesse, the father of David.
New Revised Standard Version Bible: Anglicized Edition, copyright © 1989, 1995 National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved worldwide. http://nrsvbibles.org