From Sahih Bukhari (Hadith 5307):
Narrated Ibn `Abbas:Hilal bin Umaiyya accused his wife of illegal sexual intercourse and came to the Prophet (ﷺ) to bear witness (against her), (taking the oath of Lian). The Prophet (ﷺ) was saying, "Allah knows that either of you is a liar. Will anyone of you repent (to Allah)?" Then the lady got up and gave her witness
Reference: Bukhari 5307