Jerome : (Verse 30.) After this, his brother came out, who had the scarlet thread in his hand, and his name was called Zara. This name means 'east'. Therefore, either because he appeared first, or because many righteous people were born from him, as it is written in the book of Chronicles (1 Chronicles 2 and following), he was called Zara, that is, 'east'. — Hebrew Questions on Genesis