Concerning this ḥadith, al-Tirmidhī said that it is ḥasan. The four Sunan collections likewise report the Prophet’s words: “No marriage is valid without a guardian.” These two reports—and everything else with the same meaning—show that a marriage is not valid unless a walī (legal guardian) conducts it, for the default sense of such negation is the negation of validity. Al-Tirmidhī also said: “The scholars put this ḥadith into practice; among them are ʿUmar, ʿAlī, Ibn ʿAbbās, Abū Hurayrah and others. It is likewise transmitted from the jurists of the Successors that they said, ‘No marriage is valid without a guardian,’ and this is the position of al-Shāfiʿī, Aḥmad and Isḥāq.” See al-Mughnī (6/449).

Ruling on Women Beating the Duff to Publicise a Marriage
It is recommended for women to beat the duff so that the marriage becomes known and publicised. This should take place among women only, without musical accompaniment, instruments of amusement, or the voices of female singers. There is no objection to women reciting poetry on this occasion, provided that men do not hear them, for the Messenger of Allah ﷺ said: “The distinction between what is lawful and what is unlawful is the duff and the voice at a wedding.” (1)

Al-Shawkānī said in Nayl al-Awtār (6/200): “This is evidence that at a wedding it is permissible to beat the duffs and raise the voices with words such as, ‘We have come to you, we have come to you,’ and the like—though not with songs that stir up sinful desires, contain descriptions of beauty and immorality, or speak of indulging in …”