Sahih Muslim Book - 13, Hadith - 2686

حَدَّثَنِى عَمْرُو بْنُ سَوَّادٍ الْعَامِرِىُّ أَخْبَرَنَا عَبْدُ اللَّهِ بْنُ وَهْبٍ أَخْبَرَنَا عَمْرُو بْنُ الْحَارِثِ عَنْ بُكَيْرِ بْنِ الأَشَجِّ عَنْ يَزِيدَ مَوْلَى سَلَمَةَ بْنِ الأَكْوَعِ عَنْ سَلَمَةَ بْنِ الأَكْوَعِ - رضى الله عنه - أَنَّهُ قَالَ كُنَّا فِى رَمَضَانَ عَلَى عَهْدِ رَسُولِ اللَّهِ -صلى الله عليه وسلم- مَنْ شَاءَ صَامَ وَمَنْ شَاءَ أَفْطَرَ فَافْتَدَى بِطَعَامِ مِسْكِينٍ حَتَّى أُنْزِلَتْ هَذِهِ الآيَةُ (فَمَنْ شَهِدَ مِنْكُمُ الشَّهْرَ فَلْيَصُمْهُ)

It was narrated that Salamah bin Al-Akwa [may Allah be pleased with them] said: “During Ramadan at the time of the Messenger of Allah, whoever among us wanted to fast did so, and whoever among us wanted to break the fast and pay the Fidyah did so, until this verse was revealed: ...So whoever of you sights (the crescent on the first night of ) the month (of Ramadan i.e. is resent at his home), he must observe Sawm (fasts) that month’...”[2]