Sunan of Abu Dawood Book 13, Hadith 2222

حَدَّثَنَا الزَّعْفَرَانِيُّ، حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنِ الْحَكَمِ بْنِ أَبَانَ، عَنْ عِكْرِمَةَ، أَنَّ رَجُلاً، ظَاهَرَ مِنَ امْرَأَتِهِ فَرَأَى بَرِيقَ سَاقِهَا فِي الْقَمَرِ فَوَقَعَ عَلَيْهَا فَأَتَى النَّبِيَّ صلى الله عليه وسلم فَأَمَرَهُ أَنْ يُكَفِّرَ ‏.‏

‘Ikrimah said "A man made his wife like the back of his mother. When he saw the illumination of her shin in the moonlight, he had intercourse with her. He came to the Prophet (ﷺ). He ordered him to atone for it