بُلُوغُ الْمَرَامِ
Bulugh al-Maram 519
The Book of Prayer
وَعَنْ أَنَسٍ قَالَ: { أَصَابَنَا -وَنَحْنُ مَعَ رَسُولِ اَللَّهِ- - صلى الله عليه وسلم -مَطَرٌ قَالَ: فَحَسَرَ ثَوْبَهُ, حَتَّى أَصَابَهُ مِنَ اَلْمَطَرِ, وَقَالَ: إِنَّهُ حَدِيثُ عَهْدٍ بِرَبِّهِ } رَوَاهُ مُسْلِمٌ. [1] .
Narrated [Anas (RA)]: Rain fell upon us while we were with Allah's Messenger (ﷺ). He opened his garment till some of the rain fell upon him. He then said, "It has only recently been created by its Rabb." [Reported by Muslim].
Sunnah.com reference: Book 2, Hadith 450