مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3230
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Ibn 'Abbas said - he (the narrator) said: I only think that he attributed it to the Prophet (ﷺ). He used to enjoin killing snakes and said: "Whoever leaves them alone out of fear or for fear of harm, is not one of us." And Ibn 'Abbas said: Small snakes are transformed jinn as monkeys are transformed people from among the Children of Israel.
Musnad Ahmad 3254Its isnad is saheeh]