Sunan Abu Dawud
5248
Hasan Sahih+2

Narrated AbuHurayrah: The Prophet (ﷺ) said: We have not made peace with them since we fought with them, so he who leaves any of them alone through fear does not belong to us

Hasan SahihAl-Albani
Hasan SahihMuhammad Muhyi Al-Din Abdul Hamid