Matthew 1:3

And Judas begat Phares and Zara Some have observed that these sons of Judah are mentioned together because they were twins born at the same time: but if this had been a reason for assigning Zara the honour of being named in this genealogy, Esau, the twin brother of Jacob, ought to have obtained it likewise. He seems rather to be mentioned to prevent any mistake. For if he had not, considering the infamy of Pharez's birth, we might have been apt to imagine that not the Pharez whom Judah begat in incest, but another son of Judah, called Pharez, was our Lord's progenitor, it being no uncommon thing among the Jews to have several children of the same name. Wherefore, to put the matter beyond doubt, Thamar, as well as Zara, is mentioned in the genealogy, if her name be not rather added because she was remarkable in the sacred history. This reason certainly must be assigned why three other women are named in this catalogue, viz., Rahab, Ruth, and Bathsheba. They were all remarkable characters, and their story is particularly related in the Old Testament. This seems much more probable than the opinion of those who think they are mentioned, either because they were great sinners, to teach us that Christ came to save such, or with a view to obviate the cavils of the Jews against the mean condition of the mother of our Lord; their renowned ancestors, such as even David and Solomon, being descended of women whose quality rendered them much meaner than she was. It was, however, one degree of our Saviour's humiliation, that he would be born of such sinners, and it certainly may encourage the vilest to come unto him, and expect salvation from him. Nor shall they be disappointed, if, in true repentance and lively faith, they turn from their sins to God.