148. hadíth
وَ سَأَلَهُ سَمَاعَةُ: عَنِ اَلْيَوْمِ فِي شَهْرِ رَمَضَانَ يُخْتَلَفُ فِيهِ قَالَ «إِذَا اِجْتَمَعَ أَهْلُ اَلْمِصْرِ عَلَى صِيَامِهِ لِلرُّؤْيَةِ فَاقْضِهِ إِذَا كَانَ أَهْلُ اَلْمِصْرِ خَمْسَمِائَةِ إِنْسَانٍ.
Sama'ah asked Imam (a.s) about a day in the Month of Ramadan over which there is a dispute. Imam (a.s) said: "If the people of the city agree to fast based on sighting [the crescent], then observe it. This applies if the population of the city is five hundred people."