"My wife and I were slaves, and I divorced her twice, then we were both set free. I asked Ibn 'Abbas and he said: 'If you take her back, you have two divorces left. This is how the Messenger of Allah ruled.'" (Using translation from Nasāʾī 3427)
إِنْ رَاجَعْتَهَا كَانَتْ عِنْدَكَ عَلَى وَاحِدَةٍ «قَضَى بِذَلِكَ رَسُولُ اللهِ ﷺ»