What is the ruling on someone saying to his friend, as a joke and without intent, "By God, I will slaughter you"?

An oath uttered inadvertently, without the intention of making a binding oath, falls under the category of a 'vain' or 'idle' oath (laghw al-yameen), for which there is no accountability, as Allah Almighty says: "Allah will not impose blame upon you for what is unintentional in your oaths, but He will impose blame upon you for what you intended of oaths." (Al-Ma'idah: 89). Ibn Qudamah stated that an oath that slips from one's tongue in the course of conversation without intent does not require expiation according to most scholars, because it is considered an idle oath. Nevertheless, a Muslim should guard his tongue from addressing others with offensive words and adhere to Allah Almighty’s saying: "and speak to people good words" (Al-Baqarah: 83), and His saying: "And tell My servants to say that which is best. Indeed, Satan induces [dissension] among them. Indeed, Satan is ever a clear enemy to man." (Al-Isra: 53).