Musnad Ahmad 168:5

Muhammad ibn Ubayd narrated to us, he said: Ubaydullah narrated to us, from Nafi’, from Ibn Umar, that he opened a door and a snake came out of it, so he ordered its killing. Abu Lubabah said to him: "Do not do it, for the Messenger of Allah (peace be upon him) has forbidden the killing of the jinn (snakes) that are in the houses."