The Prophet Muhammad referred to his eloquent son-in-law Ali as the "gate to the city of knowledge.” Peak of Eloquence, Nahjul Balagha, is both a compilation of Ali's sermons, letters, and sayings and a glimpse into his personality. Compiled by Sayyid al-Sharif ar-Radi more than 1, 000 years ago, it is considered a literary masterpiece and, by the Shia Muslims, the most valuable text after the Holy Qur'an.