Sahih Muslim Book - 49, Hadith - 7002

حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى حَدَّثَنَا الْمُعْتَمِرُ عَنْ أَبِيهِ حَدَّثَنَا أَبُو عُثْمَانَ عَنِ ابْنِ مَسْعُودٍ أَنَّ رَجُلاً أَتَى النَّبِىَّ -صلى الله عليه وسلم- فَذَكَرَ أَنَّهُ أَصَابَ مِنِ امْرَأَةٍ إِمَّا قُبْلَةً أَوْ مَسًّا بِيَدٍ أَوْ شَيْئًا كَأَنَّهُ يَسْأَلُ عَنْ كَفَّارَتِهَا - قَالَ - فَأَنْزَلَ اللَّهُ عَزَّ وَجَلَّ. ثُمَّ ذَكَرَ بِمِثْلِ حَدِيثِ يَزِيدَ.

It was narrated from Ibn Mas'ud that a man came to the Prophet (s.a.w) and said that he had done something with a woman, either kissing or touching her hand or something, as if he was asking about the expiation for that. Then Allah revealed (the words) ...and he (the sub narrator) mentioned a Hadith like that of Yazid (no. 7001).