As שָבָת  Shabbat, the Sabbath ends here in Israel, we say  שָׁבוּעַ   טוֹב ‏Shavua tov Good week Sunday,  יוֹם   רִאשׁוֹן Yom rishon in Hebrew,  Yom rishon, is the first day of the week.  Rishon רִאשׁוֹן means first and it is from the root רֹאשׁ Rosh, which means head.  The head of the week—Yom Rishon. יוֹם   רִאשׁוֹן Yom Rishon. יוֹם   רִאשׁוֹן  is the day of resurrection.  Yom Rishon, יוֹם   רִאשׁוֹן  the first day,  is the day of beginnings.  Look at the first word in t