The Messenger of Allah ﷺ gave judgment based on a single witness together with an oath.
حدثنا زيد بن الحباب أخبرنا سيف أخبرنا قيس بن سعد المكي عن عمرو بن دينار
أن رسول الله ﷺ قضى بشاهد ويمين
No references are available.
Its isnad is sahih. Sayf is Ibn Sulayman al-Makki. Muslim narrated the hadith at 40:2 from Abu Bakr Ibn Abu Shayba and Muhammad bin Abdullah bin Numayr, both of them from Zayd bin Hubab. It is also found in al-Muntaqa 4986, where it is likewise attributed to Abu Dawud and Ibn Majah.