مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2036
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
Moosa bin Muslim at Tahhan as-Sagheer narrated: I heard ‘Ikrimah attributing the hadeeth, as I think, to Ibn 'Abbas. He said: The Messenger of Allah (ﷺ) said: "Whoever leaves snakes alone out of fear of their pursuit is not one of us. We have not made peace with them since we fought them.”
Musnad Ahmad 2037lts isnad is saheeh]