كتاب النكاح
16
The Book of Marriage
(12)
Chapter: It is recommended for the one who wants to marry a woman to look at her face and hands before proposing marriage to her
(12)
باب نَدْبِ النَّظَرِ إِلَى وَجْهِ الْمَرْأَةِ وَكَفَّيْهَا لِمَنْ يُرِيدُ تَزَوُّجَهَا ‏

Abu Huraira (Allah be pleased with him) reported:

I was in the company of Allah's Messenger (ﷺ) when there came a man and informed him that he had contracted to marry a woman of the Ansar. Thereupon Allah's Messenger (ﷺ) said: Did you cast a glance at her? He said: No. He said: Go and cast a glance at her, for there is something in the eyes of the Ansar.
حَدَّثَنَا ابْنُ أَبِي عُمَرَ، حَدَّثَنَا سُفْيَانُ، عَنْ يَزِيدَ بْنِ كَيْسَانَ، عَنْ أَبِي حَازِمٍ، عَنْ أَبِي، هُرَيْرَةَ قَالَ كُنْتُ عِنْدَ النَّبِيِّ صلى الله عليه وسلم فَأَتَاهُ رَجُلٌ فَأَخْبَرَهُ أَنَّهُ تَزَوَّجَ امْرَأَةً مِنَ الأَنْصَارِ فَقَالَ لَهُ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ أَنَظَرْتَ إِلَيْهَا ‏"‏ ‏.‏ قَالَ لاَ ‏.‏ قَالَ ‏"‏ فَاذْهَبْ فَانْظُرْ إِلَيْهَا فَإِنَّ فِي أَعْيُنِ الأَنْصَارِ شَيْئًا ‏"‏ ‏.‏
Reference : Sahih Muslim 1424 a
In-book reference : Book 16, Hadith 87
USC-MSA web (English) reference : Book 8, Hadith 3314
  (deprecated numbering scheme)