The Messenger of Allah ﷺ said, "When one of you takes an oath, he should not say, 'Whatever Allah wills and you will,' but rather he should say, 'Whatever Allah wills, then what you will.'"
قال رسول الله ﷺ: إذا حلف أحدكم فلا يقل: ما شاء الله وشئت، ولكن ليقل: ما شاء الله ثم شئت.
Ibn Majah (2117) narrated it from Hisham bin Ammar, who said, Isa bin Yunus told us, who said, Ajlah Kindi told us, from Yazid bin Asam, from Ibn Abbas, and he related it. Its isnad is hasan, due to the discussion surrounding Ajlah, who is Ajlah bin Abdullah bin Hujayyah - with the diminutive form - known by the kunya Abu Hujayyah al-Kindi. It is said his name was Yahya. He is a subject of disagreement, Abu Dawud, Nasai, Ibn Saad, Ibn Hibban and others declared him daif, while others regarded him as acceptable. Ibn Main said, "He is sound." Ajli said, "A trustworthy Kufan." Abu Hatim said, "He is not strong, his hadith is recorded but not relied upon." Ibn Adi said, "He has sound hadiths." The conclusion is that his hadith is hasan, and in Taqrib it says, "Truthful, a Shiite." This serves as a strong corroborating witness for what preceded.This route was narrated by Imam Ahmad (2117) and Nasai (988), both with the wording, "A man came to the Prophet ﷺ and spoke to him about some matter, and said, 'What Allah wills and what you will!' The Prophet ﷺ said, 'Have you made me an equal to Allah? Rather say, what Allah alone wills.'"