Can a guardian (Wali) who is eligible to marry the woman (such as a paternal cousin, master, judge, or Sultan) marry her to himself after she gives him permission?
General Chapter
Al-Mughni
Book of Marriage
Primary text
If a guardian eligible to marry the woman grants him permission to marry her, he may do so. There are two narrations concerning his ability to handle both the offer (Ijab) and acceptance (Qabul) himself. The primary opinion, supported by Al-Hasan, Ibn Sirin, Rabi'ah, Malik, Al-Thawri, Abu Hanifah, Ishaq, Abu Thawr, and Ibn al-Mundhir, permits him to conclude both sides of the contract. The evidence cited is the narration from Al-Bukhari where Abd al-Rahman ibn Awf told Umm Hakim bint Qiraz, 'Will you entrust your affair to me?' She replied, 'Yes.' He then said, 'I have married you.' This is permissible because he possesses both the authority for offer and acceptance, just as if he were marrying his slave to his young male slave. Furthermore, the contract is valid as it involves an offer from an established guardian and acceptance from a suitable spouse.
Supporting text
The second narration states that he is not permitted to handle both sides of the contract himself, but must appoint a man to conduct the marriage on his behalf with her permission. This is attributed to Ahmad in the narration of Ibn Mansur, based on the Hadith of Al-Mughirah ibn Shu'bah, which suggests that one should delegate the marriage instead of marrying oneself, comparing it to a contract of ownership granted by permission, which prohibits handling both ends, similar to a sale.