Sunan Abu Dawud
3989
Sahih+2

Narrated Abu Hurairah:The Prophet (ﷺ) as saying - the narrator Isma'il transmitted it from Abu Hurairah, and mentioned the tradition about the coming down of revelation-: "So far (is this the case) that when terror is removed from their hearts

SahihAl-Albani
SahihMuhammad Muhyi Al-Din Abdul Hamid