"Which was the son of Phares, which was the son of Juda."
Judah "went in unto" his daughter-in-law, Tamar, who was disguised as a prostitute. She conceived and bore Pharez, an ancestor of Jesus. (Gen 38:27-29) It's a good thing it was more than ten generations ago. Otherwise Jesus could not "enter into the congregation of the Lord." (Dt.23:2) 3:33