Chapter on Oaths, Vows, and Expiations
Man Lā Yaḥḍuruh al-Faqīh|Volume 3|Book 2|Chapter 38
وَ قَالَ اَلْحَلَبِيُّ: وَ سَأَلْتُهُ عَنِ اَلرَّجُلِ يَجْعَلُ عَلَيْهِ نَذْراً وَ لاَ يُسَمِّيهِ قَالَ "إِنْ سَمَّيْتَهُ فَهُوَ مَا سَمَّيْتَ وَ إِنْ لَمْ تُسَمِّ شَيْئاً فَلَيْسَ بِشَيْءٍ فَإِنْ قُلْتَ لِلَّهِ عَلَيَّ فَكَفَّارَةُ يَمِينٍ".
Al-Halabi said: I asked Imam عليه السلام about a man who makes a vow upon himself without specifying it. Imam عليه السلام said: "If you specify it, then it is as you specified. But if you do not specify anything, then it is of no consequence. However, if you said: 'It is upon me for the sake of Allah سبحانه وتعالى,' then its expiation is the expiation of an oath."
- Ṣaḥīḥ al-Faqīh