Hadith 510980
Chapter 28: Marriage - كتاب النكاح
وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّهُ قَالَ قَالَ عُمَرُ بْنُ الْخَطَّابِ لاَ تُنْكَحُ الْمَرْأَةُ إِلاَّ بِإِذْنِ وَلِيِّهَا أَوْ ذِي الرَّأْىِ مِنْ أَهْلِهَا أَوِ السُّلْطَانِ .
Yahya related to me from Malik that he had heard that Said ibn al-Musayyab had said that Umar ibn al-Khattab said, "A woman is only married with the consent of her guardian, someone of her family with sound judgement or the Sultan.
Reference Muwatta Malik 510980
USC-MSA web (English) reference : Book 28, Hadith 5