Mishkat al-Masabih 4 Prayer كتاب الصلاة 12

وَعَنْ أَبِي ذَرٍّ أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: خَرَجَ زَمَنَ الشِّتَاءِ وَالْوَرَقُ يَتَهَافَتُ فَأَخَذَ بِغُصْنَيْنِ مِنْ شَجَرَةٍ قَالَ فَجَعَلَ ذَلِكَ الْوَرَقُ يَتَهَافَتُ قَالَ فَقَالَ: «يَا أَبَا ذَرٍّ» قُلْتُ لَبَّيْكَ يَا رَسُولَ اللَّهِ قَالَ: «إِنَّ العَبْد الْمُسلم ليصل الصَّلَاة يُرِيد بهَا وَجه الله فتهافت عَنهُ ذنُوبه كَمَا يتهافت هَذَا الْوَرَقُ عَنْ هَذِهِ الشَّجَرَةِ» . رَوَاهُ أَحْمَدُ

Abu Dharr said that the Prophet went out in winter time when the leaves were falling, and took two branches of a tree whose leaves began to fall. He then addressed Abu Dharr who replied, “At your service, Messenger of God.” He said, “A Muslim observes prayer for God’s sake and his sins fall from him as these leaves fall from this tree.” Ahmad transmitted it.