Musannaf Ibn Abi Shaybah 34255 — The virtues of Ali bin Abi Talib

Abbad bin Abdullah (may Allah have mercy on him) said that Sayyiduna Ali (may Allah be pleased with him) said: "I am the servant of Allah and the brother of His Messenger (peace and blessings be upon him), and I am al-Siddiq al-Akbar (the greatest truthful one). No one will say this after me except a lying fabricator. And I prayed seven years before the people."