The Messenger of Allah ﷺ said, "No one swears a sinful oath at this pulpit of mine, even over a green twig, without securing his seat in the Fire," or he said, "without the Fire becoming due upon him."
حدثنا عثمان بن أبي شيبة حدثنا ابن نمير حدثنا هاشم بن هاشم أخبرني عبد الله بن نسطاس من آل كثير بن الصلت أنه سمع
قال رسول الله ﷺ لا يحلف أحد عند منبري هذا على يمين آثمة ولو على سواك أخضر إلا تبوأ مقعده من النار أو وجبت له النار
Sourcing, sahih. Ibn Majah narrated it in "Rulings," chapter "The Oath at the Point of Deciding Rights," hadith 2325, from the hadith of Hashim bin Hashim through him. Ibn Hibban graded it sahih, hadith 1192, as did Ibn Jarud, hadith 927, and Hakim, 4/296-297, and Dhahabi agreed with him.