Sunan an-Nasa'i, Hadith 2335 ⓘ
It was narrated from Hafsah that she used to say: "Whoever does not intend to fast from the night before, should not fast." (Daif)
أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى، قَالَ حَدَّثَنَا مُعْتَمِرٌ، قَالَ سَمِعْتُ عُبَيْدَ اللَّهِ، عَنِ ابْنِ شِهَابٍ، عَنْ سَالِمٍ، عَنْ عَبْدِ اللَّهِ، عَنْ حَفْصَةَ، أَنَّهَا كَانَتْ تَقُولُ مَنْ لَمْ يُجْمِعِ الصِّيَامَ مِنَ اللَّيْلِ فَلاَ يَصُومُ .
also referenced under: Book 22, Hadith 246 (In-Book) & Volume 3, Book 22, Hadith 2337 (DarusSalam)