Sayyiduna Qurrah bin Iyas (may Allah be pleased with him) said: I came to the Prophet (peace and blessings be upon him) with a group from Muzaynah and we pledged allegiance to him (peace and blessings be upon him). I put my hand inside the collar of his (peace and blessings be upon him) shirt and touched the Seal of Prophethood. Urwah said: I never saw Mu'awiyah (bin Qurrah) or his son, in winter or in summer, with (the fastening of their lower garment) done up; they never fastened it.
Imam al-Tabarani (may Allah have mercy on him) said: This wording is from the narration of Ali bin Abd al-Aziz.
Hadith Referenceالمعجم الكبير للطبراني / باب القاف / 16091