Charles Ellicott Commentary Ruth 4:12

"and let thy house be like the house of Perez, whom Tamar bare unto Judah, of the seed which Jehovah shall give thee of this young woman." — Ruth 4:12 (ASV)

Pharez. —() Judah having, though unwittingly, fulfilled the Levirate obligation to the widow of his eldest son, the child thus born becomes the heir of that eldest son, and therefore the head of the house of Judah.