Ruth and BoazBoaz & Ruth - The paternal great-grandparents of King David.  Their story is recorded in the Book of Ruth, and they lived during the time of the Judges (possibly in Gideon's time, though this is not certain).  Ruth was a Moabite woman who came to Israel with her mother-in-law, Naomi, after her first husband, Naomi's son, died.  In Israel, Ruth met Boaz and they were married.


"So Boaz took Ruth, and she became his wife, and he went in to her.  And the Lord enabled her to conceive, and she gave birth to a son.  Then the women said to Naomi, 'Blessed is the Lord who has not left you without a redeemer today, and may his name become famous in Israel.  May he also be to you a restorer of life and a sustainer in your old age; for your daughter-in-law, who loves you and is better to you than seven sons, has given birth to him.'  (They said this because Naomi had lost her husband and her two sons and had no grandchildren of her own).  Then Naomi took the child and laid him on her lap, and became his nurse.  The neighbor women gave him a name, saying, 'A son has been born to Naomi!'  So they named him Obed.  He is the father of Jesse, the father of David." (Ruth 4:13-17, NASB)