Sunan Ibn Majah, Book 20, Hadith 2657 (In-Book) ⓘ
It was narrated that Qasim bin Muhammad said: “Ibn `Abbas mentioned two people who had engaged in the process of Li`an. Ibn Shaddad said to him: 'Is this the one of whom the Messenger of Allah said: “If I were to stone anyone without proof I would have stoned so-and-so.” Ibn`Abbas said: 'No, that was a woman who, (although she was a Muslim), used to expose herself.'”
حَدَّثَنَا أَبُو بَكْرِ بْنُ خَلاَّدٍ الْبَاهِلِيُّ، حَدَّثَنَا سُفْيَانُ، عَنْ أَبِي الزِّنَادِ، عَنِ الْقَاسِمِ بْنِ مُحَمَّدٍ، قَالَ ذَكَرَ ابْنُ عَبَّاسٍ الْمُتَلاَعِنَيْنِ . فَقَالَ لَهُ ابْنُ شَدَّادٍ هِيَ الَّتِي قَالَ لَهَا رَسُولُ اللَّهِ صلى الله عليه وسلم " لَوْ كُنْتُ رَاجِمًا أَحَدًا بِغَيْرِ بَيِّنَةٍ لَرَجَمْتُهَا " . فَقَالَ ابْنُ عَبَّاسٍ تِلْكَ امْرَأَةٌ أَعْلَنَتْ .
also referenced under: Hadith 2560 (Reference) & Volume 3, Book 20, Hadith 2560 (DarusSalam)