It wasnarrated that 'Imran bin Husain and Abu Barzah said:
"We wentoutwith the Messenger of Allah (ﷺ) to attend a funeral, and he sawsome people who had cast aside their upper sheets and were walking intheir shirts only. The Messenger of Allah (ﷺ) said: 'Are youadopting the practice of the days of ignorance?' or; 'Are youimitating the behaviour of the days of ignorance? I was about tosupplicate against you that you would return in a different form.'Sothey put their sheets back on and never did that again."
English reference: Vol. 1, Book 6, Hadith 1485
Arabic reference: Book 6, Hadith 1552