Al-Kāfi

Hadith 1785
15ـ الْحُسَيْنُ بْنُ مُحَمَّدٍ عَنْ مُعَلَّى بْنِ مُحَمَّدٍ عَنْ عَلِيِّ بْنِ أَسْبَاطٍ عَنْ عِدَّةٍ مِنْ أَصْحَابِنَا أَنَّ أَبَا الْحَسَنِ الأوَّلَ (عَلَيْهِ الْسَّلام) كَانَ إِذَا اهْتَمَّ تَرَكَ النَّافِلَةَ.
15. Al-Husayn ibn Muhammad has narrated from Mu‘alla’ ibn Muhammad from Ali ibn Asbat from A number of our people who has said the following: “Abu al-Hassan, the first (a.s.), whenever distressed would not perform optional Salah (prayer).”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī