The Messenger of Allah ﷺ said, "Whoever takes an oath and says, 'If Allah wills,' has not broken his oath."
أن رسول الله ﷺ قال: من حلف على يمين فقال: إن شاء الله لم يحنث.
Tirmidhi (1532), Nasai (3855), Ibn Majah (2104), and Ahmad (8088) all narrated it from the hadith of Abdul-Razzaq, and it is also in his Musannaf (16118), from Mamar, from Ibn Tawus, from his father, from Abu Hurairah, who related it. Ahmad said, Abdul-Razzaq said, "He is the one who abridged it," meaning Mamar.Tirmidhi said, I asked Muhammad bin Ismail about this hadith, and he said, "This is a mistaken hadith. Abdul-Razzaq erred in it by abridging it from the hadith of Mamar, from Ibn Tawus, from his father, from Abu Hurairah, from the Prophet ﷺ, who said, Sulayman bin Dawud said, 'Tonight I will surely go around to seventy women, and every woman will bear a boy.' So he went around to them, but not one of them bore a child except one woman, who bore half a boy. The Messenger of Allah ﷺ then said, 'Had he said, if Allah wills, it would have been as he said.'"This is how it was narrated from Abdul-Razzaq, from Mamar, from Ibn Tawus, from his father, this hadith in its full length, and he said "seventy women." This hadith has also been narrated through other channels, from Abu Hurairah, from the Prophet ﷺ, who said, "Sulayman bin Dawud said, 'Tonight I will surely go around to a hundred women.'"We have learned from what Imam Ahmad transmitted that the one who abridged it was Mamar, not Abdul-Razzaq. It may be that Abu Hurairah had two independent hadiths, one in full length and one abridged. Tawus narrated the full version from him, and his son, who is Abdullah, narrated it from him at length, while Mamar narrated the abridged version from him.