Nahj al-Balāgha
Hadith 1669٣٩. وَقَالَ (عليه السلام): لَا قُرْبَةَ بِالنَّوَافِلِ إِذَا أَضَرَّتْ بِالْفَرَائِضِ.
39. Amīr al-mu’minīn, peace he upon him, said: Supererogatory worship cannot bring about nearness to Allāh if it hampers the obligatory.