The battle cry of Banu Asad was "Ya Mabrur"

It is narrated from Sayyiduna al-Tufayl bin Amr (may Allah be pleased with him): We said: "O Messenger of Allah, make us your right flank (of the army), and make our battle cry 'Ya Mabrur' (O you who have attained righteousness)." He (peace and blessings be upon him) did so, and to this day the battle cry of the entire tribe of Azd is 'Mabrur'.
This hadith has a sahih (authentic) chain, provided that it is not mursal. And Amr bin al-Tufayl bin Amr also lived in the time of the Messenger of Allah (peace and blessings be upon him).

Muhammad bin Umar said: The father of Amr bin al-Tufayl, al-Tufayl bin Amr (may Allah be pleased with him), remained with the Messenger of Allah (peace and blessings be upon him) until he (peace and blessings be upon him) passed away. Then, when the Arabs apostatised, he went out for jihad until the Muslims were done with (the trial of) Tulayhah (the Liar) and the entire land of Najd. Then he advanced with the Muslims towards al-Yamamah, and his son Amr bin al-Tufayl was with him. Amr bin al-Tufayl went out (onto the battlefield), was wounded and his hand was cut off. Then he recovered and his wound healed. Once he was sitting with Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) when food was brought, and he moved aside from the food (because of his severed hand). Sayyiduna Umar (may Allah be pleased with him) said: "What is the matter with you that you moved aside; is it because of your hand?" He said: "Yes." Sayyiduna Umar (may Allah be pleased with him) said: "By Allah, I will not taste it until I include your (severed) hand in it. By Allah, there is no one among all these people except you, part of whose body (a hand) has gone to Paradise before him." Then, during the time of Sayyiduna Umar (may Allah be pleased with him), he went out with the Muslims to the Battle of Yarmuk and was martyred there.