حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُعَاذٍ، حَدَّثَنِي أَبِي، حَدَّثَنَا الْأَشْعَثُ، عَنْ الْحَسَنِ، فِي رَجُلٍ كَانَ بِمِصْرٍ مِنَ الْأَمْصَارِ فَصَامَ يَوْمَ الِاثْنَيْنِ، وَشَهِدَ رَجُلَانِ أَنَّهُمَا رَأَيَا الْهِلَالَ لَيْلَةَ الْأَحَدِ، فَقَالَ: "لَا يَقْضِي ذَلِكَ الْيَوْمَ الرَّجُلُ وَلَا أَهْلُ مِصْرِهِ، إِلَّا أَنْ يَعْلَمُوا أَنَّ أَهْلَ مِصْرٍ مِنْ أَمْصَارِ الْمُسْلِمِينَ قَدْ صَامُوا يَوْمَ الْأَحَدِ، فَيَقْضُونَهُ".
سنن ابودوٗد · Hadith 2333
Al-Hasan said about a person who was in a certain city. He fasted on Monday, and twp persons bore witness that they had sighted the moon on the night of sunday. He said: That man and the people of his city should not fast as an atonement except that they know (for certain) that the people of a certain city of Muslims had fasted on Sunday. In that case they should keep fast as an atonement.
Translated by Dr. Muhammad Muhsin Khan · Reviewed by Islamic University of Madinah · Published March 2020