וַֽיְהִי֙ בָּעֵ֣ת הַהִ֔וא וַיֵּ֥רֶד יְהוּדָ֖ה מֵאֵ֣ת אֶחָ֑יו וַיֵּ֛ט עַד־אִ֥ישׁ עֲדֻלָּמִ֖י וּשְׁמ֥וֹ חִירָֽה׃
And it came to pass at that time, that Judah went down from his brethren, and turned in to a certain Adullamite, whose name was Hirah.
Read halakhic rulings (Jewish law) on Genesis 38:1: and classical halakhic sources.