From Sahih Muslim (Hadith 5828):
Nafi' reported that Abu Lubaba talked to Ibn 'Umar to open a door in his house which would bring them nearer to the mosque and they found a fresh slough of the snake, whereupon 'Abdullah said:Find it out and kill it. Abu Lubaba said: Don't kill them, for Allah's Messenger (ﷺ) forbade the killing of the snakes found in houses
Reference: Muslim 5828