Often readers are tempted to skip over genealogies because they seem fairly boring and routine. But quite often important information about the identity of the final person in the genealogy is contained in the list of names. In this case, three names are very important. The first name is Perez, who was the eldest son of Tamar by Judah. Tamar's story, told in Genesis 38, bears many similarities to the book of Ruth. Tamar, like Ruth, is a foreign woman looked on with suspicion. Tamar also risks her reputation and even her life to fight for the right to have a child and thus continue the line of her dead husband.
The second important name is Boaz, the central male character in the book. He, like Judah in Genesis 38:26, recognizes Ruth as a worthy woman (Ruth 2:11-12; 3:10-11). These two names, Perez and Boaz, tie this genealogy to the earlier account of Tamar and Judah, another story of righteous persistence that led to the birth of a child and a continuation of Judah's line.
The third and most important name in the genealogy is that of David, the future king. David is the king promised by God. The people come to believe not only in the importance of David himself, but also in the importance of David's line leading ultimately to a messiah, an "anointed one." The genealogy points back to the beginning of the book, to the time of Judges in which there was not a king to stem the rise of unbridled selfishness. It then points forward to the birth of the Messiah. A version of this same genealogy, which mentions as well both Tamar and Ruth, is included in the broader genealogy that is found at the beginning of the Gospel of Matthew (1:1-17).
18 Now these are the descendants of Perez: Perez became the father of Hezron, 19Hezron of Ram, Ram of Amminadab, 20Amminadab of Nahshon, Nahshon of Salmon, 21Salmon of Boaz, Boaz of Obed, 22Obed of Jesse, and Jesse 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