I bear witness that I heard the Prophet ﷺ say, "There is no man or woman who swears a sinful oath at this pulpit, even over a fresh tooth-stick, except that the Fire becomes obligatory for them."
حدثنا أبو عاصم حدثنا الحسن بن يزيد بن فروخ الضمري من أهل المدينة قال سمعت أبا سلمة يقول سمعت
أشهد لسمعت النبي ﷺ يقول ما من عبد أو أمة يحلف عند هذا المنبر على يمين آثمة ولو على سواك رطب إلا وجبت له النار
Its chain of transmission is sahih. Al-ithm means sin. One says "athima" (with kasrah) "ithman" and "mathaman" when one falls into sin, so the person is "aathim" and "atheem."It has been reported from Ibn Masud regarding the meaning of this that the Prophet ﷺ said, "Whoever swears falsely to take the property of a Muslim without right will meet Allah while He is angry with him." He said, then the Messenger of Allah ﷺ recited to us, in confirmation of this, from the Book of Allah, "Indeed, those who exchange the covenant of Allah and their oaths for a small price, those will have no share in the Hereafter, and Allah will not speak to them, nor look at them on the Day of Resurrection, nor will He purify them, and they will have a painful punishment." [Al Imran 3:77] Agreed upon.