Sunan of Abu Dawood Book 34, Hadith 4082

حَدَّثَنَا النُّفَيْلِيُّ، وَأَحْمَدُ بْنُ يُونُسَ، قَالاَ حَدَّثَنَا زُهَيْرٌ، حَدَّثَنَا عُرْوَةُ بْنُ عَبْدِ اللَّهِ، - قَالَ ابْنُ نُفَيْلٍ ابْنُ قُشَيْرٍ أَبُو مَهَلٍ الْجُعْفِيُّ - حَدَّثَنَا مُعَاوِيَةُ بْنُ قُرَّةَ، حَدَّثَنِي أَبِي قَالَ، أَتَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم فِي رَهْطٍ مِنْ مُزَيْنَةَ فَبَايَعْنَاهُ وَإِنَّ قَمِيصَهُ لَمُطْلَقُ الأَزْرَارِ - قَالَ - فَبَايَعْتُهُ ثُمَّ أَدْخَلْتُ يَدِي فِي جَيْبِ قَمِيصِهِ فَمَسِسْتُ الْخَاتَمَ ‏.‏ قَالَ عُرْوَةُ فَمَا رَأَيْتُ مُعَاوِيَةَ وَلاَ ابْنَهُ قَطُّ إِلاَّ مُطْلِقِي أَزْرَارِهِمَا فِي شِتَاءٍ وَلاَ حَرٍّ وَلاَ يُزَرِّرَانِ أَزْرَارَهُمَا أَبَدًا ‏.‏

Mu'awiyah b. Qurrah quoted his father as saying:I came to the Messenger of Allah (ﷺ) with a company of Muzainah and we swore allegiance to him. The buttons of his shirt were open. I swore allegiance to him and I put my hand inside the collar of his shirt and felt the seal. 'Urwah said: I always saw Mu'awiyah and his son opening their buttons of the collar during winter and summer. They never closed their buttons