וַיֵּצֵ֤א הָרִאשׁוֹן֙ אַדְמוֹנִ֔י כֻּלּ֖וֹ כְּאַדֶּ֣רֶת שֵׂעָ֑ר וַיִּקְרְא֥וּ שְׁמ֖וֹ עֵשָֽׂו׃
And the first came forth ruddy, all over like a hairy mantle; and they called his name Esau.
Read halakhic rulings (Jewish law) on Genesis 25:25: and classical halakhic sources.