Sunan an-Nasa'i 2338
سنن النسائي#2338SahihIt was narrated that Hafsah that:"There is no fast for the one who does not intend to fast before dawn
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih Muquf
Al-AlbaniSahih Muquf
Zubair Ali ZaiHasan
In-book reference: 22:249