Chapter on Fasting with Authorization
Man Lā Yaḥḍuruh al-Faqīh|Volume 2|Book 2|Chapter 31
وَ رُوِيَ عَنِ اَلْعَلاَءِ عَنْ مُحَمَّدِ بْنِ مُسْلِمٍ عَنْ أَحَدِهِمَا عَلَيْهِمَا اَلسَّلاَمُ قَالَ: سَأَلْتُهُ عَنْ عَلاَمَةِ لَيْلَةِ اَلْقَدْرِ فَقَالَ «عَلاَمَتُهَا أَنْ تَطِيبَ رِيحُهَا وَ إِنْ كَانَتْ فِي بَرْدٍ دَفِئَتْ وَ إِنْ كَانَتْ فِي حَرٍّ بَرَدَتْ وَ طَابَتْ».
It is narrated from Al-Ala from Muhammad ibn Muslim, who narrated from one of the two (Imam Al-Baqir عليه السلام or Imam Al-Sadiq عليه السلام, peace be upon them), who said: "I asked him about the sign of Laylatul Qadr, and Imam عليه السلام replied: 'Its sign is that its breeze is pleasant; if it is in cold weather, it becomes warm, and if it is in hot weather, it becomes cool and pleasant.'"
- Ṣaḥīḥ al-Faqīh, p. 105