Sha’arei HaYichud VeEmunah (Gates of Unity and Faith) was written by Rabbi Aaron HaLevi Horowitz to explain and expand upon a section of the Tanya entitled Sha’ar HaYichud VeHaemunah. It discusses the nature of divine unity and the relationship between God and the universe. Although Rabbi Horowitz split from the Chabad Lubavitch movement, his work remains a respected source for understanding Lurianic kabbalah through the lens of the Tanya.