Al-Adab Al-Mufrad, Book 30, Hadith 571 (English) ⓘ

Anas said, "Rain fell on us while we were with the Prophet, may Allah bless him and grant him peace, took of his garment so that the rain could fall on him. We said, 'Why did you do that?' He said, 'Because it has newly come from its Lord.'"

حَدَّثَنَا عَبْدُ اللهِ بْنُ أَبِي الأَسْوَدِ، قَالَ‏:‏ حَدَّثَنَا جَعْفَرُ بْنُ سُلَيْمَانَ، عَنْ ثَابِتٍ، عَنْ أَنَسٍ قَالَ‏:‏ أَصَابَنَا مَعَ النَّبِيِّ صلى الله عليه وسلم مَطَرٌ، فَحَسَرَ النَّبِيُّ صلى الله عليه وسلم ثَوْبَهُ عَنْهُ حَتَّى أَصَابَهُ الْمَطَرُ، قُلْنَا‏:‏ لِمَ فَعَلْتَ‏؟‏ قَالَ‏:‏ لأَنَّهُ حَدِيثُ عَهْدٍ بِرَبِّهِ‏.‏