The Messenger of Allah ﷺ said, "There is no fast for the one who does not resolve upon it from the night before."
حدثنا أبو بكر بن أبي شيبة حدثنا خالد بن مخلد القطواني عن إسحق بن حازم عن عبد الله بن أبي بكر بن عمرو بن حزم عن سالم عن ابن عمر
قال رسول الله ﷺ لا صيام لمن لم يفرضه من الليل
No references are available.
Sourcing, its chain is daif. Abu Dawud narrated it in the book of Fasting, chapter on intention in fasting, no. 2454, and others narrated it with a strong chain, from Abdullah bin Abu Bakr, from Zuhri, from Salim, with the same wording. Tirmidhi considered it gharib, no. 730, while Ibn Khuzayma and Hakim graded it sahih. Zuhri's use of "an" (indicating indirect transmission) was noted earlier, no. 707. Nasai narrated it, 4/197, no. 2338, with a chain as sahih as the sun, from Hafsa, who said, "There is no fast for one who has not resolved on it before Fajr," as a report stopped at Hafsa herself.