Genesis 38:30 Commentary - Companion Bible Notes, Appendices and Graphics

Zarah = "a rising of light", "Offspring", or "Dawn". Both Pharez and Zarah, together with their rnother Tamar, are in the genealogy of Christ (Mat 1:3). This is why this parenthetical chapter is inserted here. It is here by the Figure of speech Parecbasis. It comes, historically, before chapter 37.