Al-Kāfi

Hadith 507
fastingtravel-prayer
2ـ عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ ابْنِ أَبِي عُمَيْرٍ عَنْ بَعْضِ أَصْحَابِهِ قَالَ لا يُفْطِرُ الرَّجُلُ فِي شَهْرِ رَمَضَانَ إِلاَّ فِي سَبِيلِ حَقٍّ.
2. Ali ibn Ibrahim has narrated from his father from Ibn Abi ‘Umayr from certain persons of our people who has said the following: “He (the Imam) (a.s.), has said, ‘One must not stop fasting in the month of Ramadan except in the way of truth.’”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī