Al-Kāfi
Hadith 5302ـ أَحْمَدُ بْنُ مُحَمَّدٍ عَنْ مُحَمَّدِ بْنِ سَهْلٍ عَنْ أَبِيهِ قَالَ سَأَلْتُ أَبَا الْحَسَنِ (عَلَيْهِ السَّلاَم) عَنْ رَجُلٍ أَتَى أَهْلَهُ فِي شَهْرِ رَمَضَانَ وَهُوَ مُسَافِرٌ قَالَ لا بَأْسَ.
2. Ahmad ibn Muhammad has narrated from Muhammad ibn Sahl [from his father] who has said the following: “I once asked abu al-Hassan (a.s.), about a man who experiences sexual relation with his wife in the month of Ramadan during a journey. He (the Imam) said, ‘It is not harmful.’”