He Swore to Divorce Forgetfully

Question :

A man swore to divorce due to forgetfulness after being recently married. He said: "I must divorce next year if I do not purchase such-and-such." If he did not purchase (that thing), is his wife divorced? And if he did not purchase it, what is incumbent upon him, bearing in mind that it is not his custom to swear to divorce to the extent that he sought forgiveness from Allah.

Answer:

The ruling on sayings such as this differs depending upon the intention of the husband. If his intention was to encourage and to incite himself to buy something and he did not intend to part from his wife if he did not purchase the thing he mentioned in his oath to divorce then this divorce will fall under the ruling of an oath, according to the most authoritative saying of the scholars. Then he must make the atonement for it, which is to feed ten poor persons, giving each of them half a Sa' of the staple food of the country, such as dates or some such thing. That is equivalent to approximately one and a half kilograms. If he gave dinner to the ten or fed them lunch, or clothed them in garments fitting for prayer, that would be sufficient for him.

However, if his intention was that the divorce of his wife should take place if he did not purchase the thing, then the divorce would be counted upon her. It is desirable for a believer to avoid the use of divorce in these conditional pronunciations, because many of the scholars consider that divorce has taken place in all such cases. And the Prophet ﷺ said:
"Whoever avoided the unclear matters, has saved his religion and his honor."

Source:
Ibn Baz
Fatawa Islamiyah, Vol. 6 Pages 389-390