Sunan Ibn Majah, Volume 2, Book 7, Hadith 1760 (DarusSalam) ⓘ

It was narrated that ‘Atiyyah bin Sufyan bin ‘Abdullah bin Rabi’ah said: “Our delegation who went to the Messenger of Allah to announce the Islam of Thaqif told us that they came to him in Ramadan. He set up a tent for them in the mosque, and when they became Muslim, they fasted what was left of the month.”

حَدَّثَنَا مُحَمَّدُ بْنُ يَحْيَى، حَدَّثَنَا أَحْمَدُ بْنُ خَالِدٍ الْوَهْبِيُّ، حَدَّثَنَا مُحَمَّدُ بْنُ إِسْحَاقَ، عَنْ عِيسَى بْنِ عَبْدِ اللَّهِ بْنِ مَالِكٍ، عَنْ عَطِيَّةَ بْنِ سُفْيَانَ بْنِ عَبْدِ اللَّهِ بْنِ رَبِيعَةَ، قَالَ حَدَّثَنَا وَفْدُنَا الَّذِينَ، قَدِمُوا عَلَى رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ بِإِسْلاَمِ ثَقِيفٍ ‏.‏ قَالَ وَقَدِمُوا عَلَيْهِ فِي رَمَضَانَ وَضَرَبَ عَلَيْهِمْ قُبَّةً فِي الْمَسْجِدِ فَلَمَّا أَسْلَمُوا صَامُوا مَا بَقِيَ عَلَيْهِمْ مِنَ الشَّهْرِ ‏.‏