The Messenger of Allah ﷺ said, "The defendant has the greater right to take the oath, unless clear evidence is presented."
أن رسول الله ﷺ قال: المدعى عليه أولى باليمين إلا أن تقوم بينة.
Ibn Hibban (5996) narrated it in a lengthy version, and Daraqutni (4511) narrated it in an abridged form, both from the hadith of Sinan bin Harith bin Musrif, from Talha bin Musarrif, from Mujahid, from Ibn Umar, who said, and he mentioned it. Its chain is hasan because of Sinan bin Harith, for a number of narrators related from him, Ibn Hibban mentioned him among the trustworthy narrators, and included his hadith in his Sahih, and it has a firm basis. It is further strengthened by the hadith, "Your two witnesses or his oath," so a narrator like him has his hadith graded hasan, and this is one of them.