Ruth was a Moabite. She was "grafted" into the family of Jehovah because of her faith (see Romans 11). She was not a member of God's family by birth, but by new birth.
If you ever wonder whether there is a place for you in the family of Jesus Christ, look no further than page one of your New Testament.
Matthew 1:1-17; NKJV
1 The book of the genealogy of Jesus Christ, the Son of David, the Son of Abraham:
2 Abraham begot Isaac, Isaac begot Jacob, and Jacob begot Judah and his brothers. 3 Judah begot Perez and Zerah by Tamar, Perez begot Hezron, and Hezron begot Ram. 4 Ram begot Amminadab, Amminadab begot Nahshon, and Nahshon begot Salmon. 5 Salmon begot Boaz by Rahab, Boaz begot Obed by Ruth, Obed begot Jesse, 6 and Jesse begot David the king.
David the king begot Solomon by her who had been the wife of Uriah. 7 Solomon begot Rehoboam, Rehoboam begot Abijah, and Abijah begot Asa. 8 Asa begot Jehoshaphat, Jehoshaphat begot Joram, and Joram begot Uzziah. 9 Uzziah begot Jotham, Jotham begot Ahaz, and Ahaz begot Hezekiah. 10 Hezekiah begot Manasseh, Manasseh begot Amon, and Amon begot Josiah. 11 Josiah begot Jeconiah and his brothers about the time they were carried away to Babylon.
12 And after they were brought to Babylon, Jeconiah begot Shealtiel, and Shealtiel begot Zerubbabel. 13 Zerubbabel begot Abiud, Abiud begot Eliakim, and Eliakim begot Azor. 14 Azor begot Zadok, Zadok begot Achim, and Achim begot Eliud. 15 Eliud begot Eleazar, Eleazar begot Matthan, and Matthan begot Jacob. 16 And Jacob begot Joseph the husband of Mary, of whom was born Jesus who is called Christ.
17 So all the generations from Abraham to David are fourteen generations, from David until the captivity in Babylon are fourteen generations, and from the captivity in Babylon until the Christ are fourteen generations.