Zayd bin Thabit reported,

When the Prophet ﷺ set out for Uhud, some of those who had gone with him turned back. The Prophet's companions then split into two groups, one saying, "We should fight them," and the other saying, "We should not fight them." So the verse was revealed, "What is the matter with you that you are divided into two groups regarding the hypocrites, while Allah has cast them back because of what they earned?" [Nisa 4:88].And he said, "It is Taybah. It removes sins just as fire removes the impurities of silver."

Bukhari 4050

Sahih

حدثنا أبو الوليد حدثنا شعبة عن عدي بن ثابت سمعت عبد الله بن يزيد يحدث

عن زيد بن ثابت رضي الله عنه قال

لما خرج النبي ﷺ إلى أحد رجع ناس ممن خرج معه وكان أصحاب النبي ﷺ فرقتين فرقة تقول نقاتلهم وفرقة تقول لا نقاتلهم فنزلت {فما لكم في المنافقين فئتين والله أركسهم بما كسبوا} وقال إنها طيبة تنفي الذنوب كما تنفي النار خبث الفضة

البخاري 4050صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Bukhari
Book
Expeditions
Chapter
Uhud expedition
Numbering
Darussalam 4050
Bukhari 4050