It was narrated from Abu Hurairah that the Messenger of Allah (ﷺ) said:
'Whoever swears an oath and says In sha' Allah, he will have made an exception."(2) (JA)
English reference (JA): Vol. 3, Book 11, Hadith 2104 (JA)
Arabic reference (JA): Book 11, Hadith 2182 (JA)