كتاب النكاح
16
The Book of Marriage
(9)
Chapter: Seeking permission of a previously-married woman in words, and of a virgin by silence
(9)
باب اسْتِئْذَانِ الثَّيِّبِ فِي النِّكَاحِ بِالنُّطْقِ وَالْبِكْرِ بِالسُّكُوتِ ‏

Abu Huraira (Allah be pleased with him) reported Allah's Messenger (ﷺ) as having said:

A woman without a husband (or divorced or a widow) must not be married until she is consulted, and a virgin must not be married until her permission is sought. They asked the Prophet of Allah (ﷺ): How her (virgin's) consent can be solicited? He (the Holy Prophet) said: That she keeps silence.
حَدَّثَنِي عُبَيْدُ اللَّهِ بْنُ عُمَرَ بْنِ مَيْسَرَةَ الْقَوَارِيرِيُّ، حَدَّثَنَا خَالِدُ بْنُ الْحَارِثِ، حَدَّثَنَا هِشَامٌ، عَنْ يَحْيَى بْنِ أَبِي كَثِيرٍ، حَدَّثَنَا أَبُو سَلَمَةَ، حَدَّثَنَا أَبُو هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ لاَ تُنْكَحُ الأَيِّمُ حَتَّى تُسْتَأْمَرَ وَلاَ تُنْكَحُ الْبِكْرُ حَتَّى تُسْتَأْذَنَ ‏"‏ ‏.‏ قَالُوا يَا رَسُولَ اللَّهِ وَكَيْفَ إِذْنُهَا قَالَ ‏"‏ أَنْ تَسْكُتَ ‏"‏ ‏.‏
Reference : Sahih Muslim 1419 a
In-book reference : Book 16, Hadith 75
USC-MSA web (English) reference : Book 8, Hadith 3303
  (deprecated numbering scheme)