حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّهُ كَانَ يَقُولُ لاَ يَصُومُ إِلاَّ مَنْ أَجْمَعَ الصِّيَامَ قَبْلَ الْفَجْرِ ‏.‏

Yahya related to me from Malik from Nafi that Abdullah ibn Umar used to say, "Only some one who makes the intention to fast before dawn (actually) fasts." Translation Not Available

Book Ref: Muwatta Imam Malik Book 18 Hadith 637
Web Ref:  Muwatta Imam Malik Book 18 Hadith 5

---