It was narrated from Ibn 'Umar that the Prophet said: "Whoever swears an oath and says: “If Allah wills', then if he wishes he may go ahead, and if he wishes he may not, without having broken his oath”"
SahihSahihIsnaad SahihBook 35 · Hadith 33
سنن النسائي
It was narrated from Ibn 'Umar that the Prophet said: "Whoever swears an oath and says: “If Allah wills', then if he wishes he may go ahead, and if he wishes he may not, without having broken his oath”"