عَنْ أَنَسٍ بْنِ مَالِكٍ رَضِيَ اللَّهُ عَنْهُ قَالَ: مُطِرْنَا عَلَى عَهْدِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ قَالَ: فَخَرَجَ فَحَسَرَ ثَوْبَهُ حَتَّى أَصَابَهُ الْمَطَرُ، قَالَ: فَقِيلَ لَهُ: يَا رَسُولَ اللَّهِ! لِمَ صَنَعْتَ هَٰذَا؟ قَالَ: لِأَنَّهُ حَدِيثُ عَهْدٍ بِرَبِّهِ
Sayyiduna Anas bin Malik (may Allah be pleased with him) says: During the time of the Messenger of Allah (peace and blessings be upon him), rain fell upon us. The Prophet (peace and blessings be upon him) came out, removed (some part of) his garment from his body until the rain touched it. He was asked: O Messenger of Allah! Why did you do this? The Prophet (peace and blessings be upon him) replied: Because it has just come freshly from Allah, the Exalted.