Jami` at-Tirmidhi, Volume 2, Book 6, Hadith 693 (DarusSalam) ⓘ

Muhammad bin Abi Harmalah narrated: "Kuraib informed me that Umm Al-Fadl bin Al-Harith sent him to Mu'awiyah in Ash-Sham. He said: 'So I arrived in Ash-Sham and finished her errand, and I saw the crescent of Ramadan while I was in Ash-Sham. We saw the crescent on the night of Friday. Then I arrived in Al-Madinah at the end of the month. Ibn Abbas was questioning me, then he mentioned the crescent and he said: "When did you see the crescent?" I said: "We saw it n the night of Friday." He said: "Did you see it on the night of Friday?" I said: "The people saw it, so they fasted, and Mu'awiyah fasted." He said: "But we saw it on the night of Saturday, so we will not stop fasting until we complete thirty days or we see it." So I said: "Is not the sighting and fasting of Mu'awiyah enough for you?" He said: "This is not how the Messenger of Allah ordered us."

حَدَّثَنَا عَلِيُّ بْنُ حُجْرٍ، حَدَّثَنَا إِسْمَاعِيلُ بْنُ جَعْفَرٍ، حَدَّثَنَا مُحَمَّدُ بْنُ أَبِي حَرْمَلَةَ، أَخْبَرَنِي كُرَيْبٌ، أَنَّ أُمَّ الْفَضْلِ بِنْتَ الْحَارِثِ، بَعَثَتْهُ إِلَى مُعَاوِيَةَ بِالشَّامِ ‏.‏ قَالَ فَقَدِمْتُ الشَّامَ فَقَضَيْتُ حَاجَتَهَا وَاسْتُهِلَّ عَلَىَّ هِلاَلُ رَمَضَانَ وَأَنَا بِالشَّامِ فَرَأَيْنَا الْهِلاَلَ لَيْلَةَ الْجُمُعَةِ ثُمَّ قَدِمْتُ الْمَدِينَةَ فِي آخِرِ الشَّهْرِ فَسَأَلَنِي ابْنُ عَبَّاسٍ ثُمَّ ذَكَرَ الْهِلاَلَ فَقَالَ مَتَى رَأَيْتُمُ الْهِلاَلَ فَقُلْتُ رَأَيْنَاهُ لَيْلَةَ الْجُمُعَةِ ‏.‏ فَقَالَ أَأَنْتَ رَأَيْتَهُ لَيْلَةَ الْجُمُعَةِ فَقُلْتُ رَآهُ النَّاسُ وَصَامُوا وَصَامَ مُعَاوِيَةُ ‏.‏ قَالَ لَكِنْ رَأَيْنَاهُ لَيْلَةَ السَّبْتِ فَلاَ نَزَالُ نَصُومُ حَتَّى نُكْمِلَ ثَلاَثِينَ يَوْمًا أَوْ نَرَاهُ ‏.‏ فَقُلْتُ أَلاَ تَكْتَفِي بِرُؤْيَةِ مُعَاوِيَةَ وَصِيَامِهِ قَالَ لاَ هَكَذَا أَمَرَنَا رَسُولُ اللَّهِ صلى الله عليه وسلم ‏.‏ قَالَ أَبُو عِيسَى حَدِيثُ ابْنِ عَبَّاسٍ حَدِيثٌ حَسَنٌ صَحِيحٌ غَرِيبٌ ‏.‏ وَالْعَمَلُ عَلَى هَذَا الْحَدِيثِ عِنْدَ أَهْلِ الْعِلْمِ أَنَّ لِكُلِّ أَهْلِ بَلَدٍ رُؤْيَتَهُمْ ‏.‏