8th Day is an American Chasidic pop rock band based in Los Alamitos, California. Formed in 2004 by brothers Shmuel and Bentzion Marcus, Both nephews of singer Avraham Fried and cousins of singer Benny Friedman, They grew up in a musically-inclined family and began collaborating in 2004, with Bentzi, a professional bassist, putting music to lyrics Shmuel had written.

That same year, the pair recorded a four-song demo with their brother Chaim Marcus producing. Their debut studio album, "Tracht Gut" was released on April 1, 2005 and featured Chaim, Zalman, Yossi, and Eli