Selections from The Sayings and Preaching of Amir al-Muminin Ali ibn Abi Talib (Peace Be Upon Him) Including His Replies to Questions and Maxims Expressed for Various Purposes.Translated by Sayyid Ali Reza
وَقَالَ (عليه السلام):
Amir al-mu'minin, peace be upon him, said:
مَنْ قَضَى حَقَّ مَنْ لاَ يَقْضِي حَقَّهُ
He who fulfils the right of a man who does not fulfil his right,
فَقَدْ عَبَدَهُ.
(is as though he) worships him.