Sunnah.com reference : Book 8, Hadith 115English translation : Book 8, Hadith 0Arabic reference : Book 8, Hadith 1065
Another narration by him has:
"He commanded him to divorce her."
وَفِي رِوَايَةٍ لَهُ : { وَأَمَرَهُ بِطَلَاقِهَا }   1‏ .‏‏1 ‏- صحيح .‏ رواه البخاري ( 9 / 395 / فتح )‏.‏