Sunan an-Nasa'i 3830
سنن النسائي#3830SahihIt was narrated from Ibn 'Umar that the Messenger of Allah said:"Whoever swears an oath and says, 'If Allah wills,' then he has the choice: If he wishes, he may go ahead, and if he wishes he may not
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiHasan
In-book reference: 35:70