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:
لاَ قُرْبَةَ بِالنَّوَافِلِ
Supererogatory worship cannot bring about nearness to Allah
إِذَا أَضَرَّتْ بِالْفَرَائِضِ
if it hampers the obligatory.