Habib Ibn Muzahir sought the permission of Imam Husayn (‘a) to go to Banu Asad who were domiciled nearby, and permission was granted to him. When he came to them and identified himself as one of their tribesmen, they, indeed, came to recognize him.
He, then, asked them to support the son of the daughter of the Messenger of Allah (S), for that, he told them, would bring them honour in this life and honour in the life hereafter. Ninety men responded to his call. One man slipped away from their quarters to inform Ibn Sa’d of what had happened there.
The latter instantly sent four hundred men as enforcement to al-Azraq's men in order to intercept that small band on the highway. A fight broke out, and a number of men belonging to Banu Asad were killed while those who survived fled away back home.
Banu Sa’d, fearing a sudden attack from Ibn Sa’d, moved out of that area in their entirety under the cover of the night. Habib went back to al-Husayn (‘a) and told him about what had happened. The Imam (‘a) said, “La hawla wala quwwata illa billahil ‘aliyy al-’azeem,” that is, “There is neither power, nor might, except in Allah, the most Exalted One, the Great.”
(al-Majlisi, Bihar al-Anwar, quoting Maqtal Muhammad Ibn Abu Talib. Al-Khawarizmi, Maqtal al-Husayn, Vol. 1, p. 243.)