Sayyiduna Abu Musa (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "There is no marriage without a guardian." Ibn Askar said: Qabisah bin Uqbah said to me: Ali bin al-Madini came to me and asked me about this hadith, so I narrated it to him, and Ali bin al-Madini said: Now we are relieved of the disagreement over Abu Ishaq.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13628