Tzemach Tzedek

Menachem Mendel Schneersohn (September 9, 1789 – March 17, 1866) also known as the Tzemach Tzedek (Hebrew: "Righteous Sprout" or "Righteous Scion") was an Orthodox, leading 19th-century posek, and the third rebbe (spiritual leader) of the Chabad Lubavitch Hasidic movement.

Quotes

 * Tracht gut, vet zein gut
 * Think good, and it will be good.
 * "Good Thinking", Chabad.org