Sayyiduna Abu Layla (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Whoever sees a snake and then does not kill it, out of fear of its pursuit, is not one of us."
Al-Tabarani recorded it in al-Mu'jam al-Kabir; its chain contains a narrator, Muhammad bin Abi Layla, who has a poor memory, and the remaining narrators of this report are thiqat (trustworthy).