(33) باب مَا جَاءَ لاَ صِيَامَ لِمَنْ لَمْ يَعْزِمْ مِنَ اللَّيْلِ
Hafsah narrated that:
the Prophet said: "Whoever did not decide to fast before Fajr then there is no fast for him." (RU)
Reference (RU): Jami` at-Tirmidhi 730 (RU)
In-book reference (RU): Book 8, Hadith 49 (RU)
English translation (RU): Vol. 2, Book 3, Hadith 730 (RU)