Abu Al-Ahwas Al-Jashami narrates that one day Sayyiduna Ibn Mas'ud (may Allah be pleased with him) was delivering a sermon when suddenly his gaze fell upon a snake crawling on the wall. He stopped his speech and struck it with his staff until it died. Then he said: I heard the Prophet (peace and blessings be upon him) say, "Whoever kills a snake, it is as if he has killed a polytheist whose blood is lawful."