Imam Ali (A.S) always ate and dressed in such a simple way that even the poorest could afford better. It was not because he was poor, but it was because he wanted to lead the life of the poorest person and spend all that could thus be spared on the poor. I have noted below certain cases quoted by the historians. These incidents are of the time when he was the ruler of the entire Muslim Empire, except Syria.
Suwayda bin Ghafla says: "One day I went to see Imam Ali (A.S) in the Government House (Darul Imarah). It was the time of breakfast and before him there was a cup of milk and some barley bread. The bread was dry, stale, hard and did not contain any butter or oil. It could not be easily broken into pieces. Imam Ali (A.S) was exerting himself to break it and to soften it. I turned towards the maid-servant, Fizza and said, 'Fizza! Have you no pity upon your old master, and why can't you give him softer bread and add some butter or oil to it?' She replied, "Why should I pity him when he never pities himself. He has given strict orders that nothing is to be added to his bread and even chaff and husks are not to be separated from the flour. We, ourselves eat much better food than this, although we are his servants." Hearing this, I told him, "O master! Have pity on yourself; look at your age, your responsibilities, your hard work and your food." He replied, "O Suwayda! You have no idea what the Holy Prophet (P.B.U.H) used to eat. He never ate his fill for three consecutive days."
Abdullah ibn Zurarah says: "I went to see Imam Ali (A.S) on a festival (Eid) day. He asked me to join in his breakfast. I consented. A very simple kind of food was served before us. I told him, "O master! You are such a rich man and a caliph. I was expecting that a game would be served before us but what do I see?" The great Imam replied, "Ibn Zurarah, you have heard of mighty kings who have led life of luxury. Let me be a ruler leading the life of a poor and humble person -- a humble labourer."
Ibn Abi Rafe', the famous Tabe'i, says: He went to Imam Ali (A.S) on a festival (Eid) day and while he was sitting there, a bag was brought before the Imam; he thought it might contain jewels. The Imam opened the bag; it contained dried pieces of bread, which he softened with water. Ibn Abi Rafe' asked him as to the reason of sealing such a kind of food which even a beggar would not care to steal. The Imam (A.S) smiled and said: "I keep it sealed because my children try to substitute softer bread, containing oil or butter in it." Ibn Abi Rafe' said, "Has Allah prohibited you to eat a better kind of food?" He replied: "No, but I want to eat the kind of food which the poorest of this region can afford at least once a day. I shall improve it after I have improved their standard of life. I want to live, feel and suffer like them".
Harun ibn Anza said that he accompanied his father (Anza) to meet Imam Ali (A.S), in winter days and the winter was very severe. He found the Imam in a very thin cotton garment, and the cold wind was making him shiver. Anza asked him, "O Commander of the Faithful! Allah has reserved a share for you and your family from Public Treasury why do you not make use of it?" He replied: "O Anza! I don't want anything from your treasury; this is the dress I have brought with me from Medina."
Zayd ibn Wahab said that once Imam Ali (A.S) came out of his house and there were patches sewn to his dress. Ibn Nu'aja, who was once a Kharijite and an enemy and yet he was allowed to lead a peaceful and comfortable life by Imam at Kufa, once taunted Imam Ali (A.S) on the very poor and coarse kind of dress put on by him. He replied: "Let go, what have you to find objection in my dress, it is the kind which our masses can afford, why can't you think of their lives and dresses! I shall improve my standard after I have succeeded in improving theirs. I shall continue to live like them. Such a kind of dress makes one feel humble and meek and give up vanity, haughtiness and arrogance."
Amr ibn A'iz narrated that once he asked Imam Ali as to the reason of his having patches in his dress, he replied: "O Amr, such type of dress makes you soft-hearted, vanishes vanity from your mind and it is the kind which poor Muslims can conveniently afford.". (See also Nahjul Balagha, Saying 103)
Hasan bin Jurmuz narrates that his father once saw Imam Ali coming out of Kufa Mosque in a shirt made of jute cloth and around him were people so well-dressed that compared to him they looked like princes, he was advising them as how to understand religion.
Abu Nuziya, the draper of Kufa narrates that Imam Ali purchased two shirts from his shop; one was of superior quality, which he handed over to his slave Qambar to put on and the other which was cheap and coarse, reserved it for himself. [20] (See more about Imam Ali's dress and food in Nahjul Balagha, Letter45 and Sermon207)
source : sibtayn
