The Prophet ﷺ said, "Whoever takes an oath and says, 'If Allah wills,' has made an exception, so he bears no liability for breaking it."
أن النبي ﷺ قال: من حلف فقال: إن شاء، فقد استثنى، فلا حنث عليه.
It was narrated by Abu Dawud (3262/3261), Tirmidhi (1531), Nasai (3829), and Ibn Majah (2105), and Ibn Hibban (4339) and Hakim (4/303) both graded it sahih. All of them narrated it through Ayub, from Nafi, from Ibn Umar, who related it. Tirmidhi said, "A hasan hadith," and Hakim said, "Sahih according to the criterion of Bukhari."Kathir bin Farqad corroborated him, narrating it from Nafi in this same way as a raised hadith. Nasai (3828) and Hakim also narrated it through his route. Kathir bin Farqad is trustworthy, Ibn Main deemed him trustworthy, and Abu Hatim said he was upright. He is among the narrators relied upon by Bukhari.Likewise, Ayub bin Musa also corroborated him, narrating from Nafi, and Ibn Hibban (4340) narrated it through his route. Ayub bin Musa is Ibn Amr bin Saeed bin As, from Makkah, of the Umayyad clan, a trustworthy and precise memorizer, among the narrators relied upon by the wider community of scholars.However, Tirmidhi found fault with it, saying, "Ubaydullah bin Umar and others have narrated it from Nafi, from Ibn Umar, as a stopped report." It has likewise been narrated from Salim, from Ibn Umar, as a stopped report, and we do not know of anyone who raised it to the Prophet except Ayub Sakhtiyani. Ismail bin Ibrahim said, "Ayub would sometimes raise it and sometimes not raise it."Bayhaqi (10/46) said, after quoting the discussion about Ayub raising this hadith and then abandoning that practice, "It has also been narrated from Musa bin Uqba, Abdullah bin Umar, Hassan bin Atiya, and Kathir bin Farqad, from Nafi, from Ibn Umar, from the Prophet ﷺ. Its being raised to the Prophet can scarcely be established as sound except through Ayub Sakhtiyani, and even Ayub was uncertain about it. The narration of the group of narrators, through sound routes, from Nafi, from Ibn Umar, is as his own statement, not raised to the Prophet."I say, the default position for this hadith is that it should be raised to the Prophet, since this is not a matter open to independent reasoning. So if the trustworthy narrators added to it and raised it, then their statement takes precedence.As for what is narrated from Ibn Abbas, that he said, the Messenger of Allah ﷺ said, "By Allah, I will surely raid Quraysh, by Allah, I will surely raid Quraysh, by Allah, I will surely raid Quraysh," then he fell silent and said, "If Allah wills," this is daif. It was narrated by Simak, from Ikrima, from Ibn Abbas.Abu Yaala (2675) narrated it, and Ibn Hibban (4343) narrated it through him, via the route of Ali bin Mushir, from Misar bin Kidam, from Simak bin Harb, in this way, raised to the Prophet. Simak is inconsistent in his transmission from Ikrima.Abu Dawud (3285) narrated it, and Bayhaqi (10/47-48) narrated it through his route, from Qutayba bin Saeed, who said, Sharik narrated to us, from Simak, from Ikrima, that the Messenger of Allah ﷺ said, and he related something similar. Abu Dawud said, "More than one narrator has narrated this hadith with a full chain from Sharik, from Ikrima, from Ibn Abbas, connecting it to the Prophet. Walid bin Muslim said, on the authority of Sharik, 'Then he did not raid them.'"Sharik is poor in his memory, and the hadith hinges on him, and the disconnected version is sounder than his account. This is also the view favored by Abu Hatim, as found in Ilal (1/440), and by Ibn Munzir in Awsat (12/160).Moreover, this hadith is not sound in terms of its meaning. Walid bin Muslim reported from Sharik that the Prophet ﷺ did not raid them, that is, after the oath. If his oath was before the conquest of Makkah, then he did in fact raid them, and if it was after the conquest of Makkah, then why would he swear to raid them when they had already entered Islam?It is also not sound from the standpoint of jurisprudence. Khattabi, after quoting Ibn Abbas's statement that he retained the right to make his exception even after some time had passed, said, "The generality of the people of knowledge hold a view opposite to that of Ibn Abbas and his companions. Had the matter been as they claimed, the one who swears an oath would always have a way out of it, such that no atonement would ever be required of him. It has been established from the Prophet ﷺ that he said, 'Whoever swears an oath and then sees that something else is better, let him do what is better and let him make atonement for his oath.'The scholars do not disagree that if the exception is joined immediately to the oath, no atonement is required of him. They disagree about the exception when it is separated from the oath. Most of the people of knowledge hold that it has no effect unless there is only a brief pause between the oath and the exception, like the pause of a man collecting his thoughts, or catching his breath. But if the interval is long, or he occupies himself with other speech in between and then makes his exception, it is not valid. This is because the statement of the Prophet ﷺ, 'Whoever swears an oath and then makes an exception,' implies that it must directly follow it, and because the exception is part of completing the statement, so its connection to it is required, like a conditional clause and its response.It has been narrated from Ibn Abbas that he permitted the exception even after some time had passed, and his companions held that the exception was permissible up to a year later. It is narrated from Imam Ahmad that the exception is permissible as long as the interval between the two is not long. In another report from him, provided he has not mixed his speech with anything else, Ismail bin Saeed transmitted something similar from him, and added that he said, 'I do not hold the view of those,' meaning those who did not consider it valid unless it was immediately connected. Ibn Qudama mentioned this in Mughni (13/485)."