Abu Bishr narrated from Tawus (may Allah have mercy on him), Ata' (may Allah have mercy on him) and the people of Madinah that they said: "The one in whose hand is the marriage tie" [Surah al-Baqarah: 237] is the guardian. He said: I informed them of the view of Sa'id bin Jubayr (may Allah have mercy on him) that it is the husband, and they retracted their view. When Sa'id bin Jubayr (may Allah have mercy on him) came, he asked: What do you think: if the guardian forgoes the dowry and the woman refuses, what use is the guardian's forgoing? Or if she forgoes it and the guardian refuses, what does the guardian have to do with it?
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14453