In the name of Allah, the Most Compassionate, the Most Merciful.
From Muhammad, the Prophet and Messenger of Allah, to Khalid ibn al-Walid.
Peace be upon you. I praise Allah to you—there is no deity but He.
To proceed: Your letter has reached me by the hand of your messenger, informing me that the Banu al-Harith ibn Kaʿb have embraced Islam before you fought them, that they accepted what you invited them to of Islam, testified that there is no deity but Allah and that Muhammad is the servant and Messenger of Allah, and that Allah has guided them by His guidance. Give them glad tidings and warnings, then return, and let their delegation return with you.
Peace be upon you, and the mercy of Allah and His blessings.

Khalid thereupon returned to the Messenger of Allah ﷺ, accompanied by the delegation of Banu al-Harith ibn Kaʿb. Among them were Qays ibn al-Husayn—known as Dhū’l-Ghussah—Yazid ibn ʿAbd al-Madan, Yazid ibn al-Muhajjal, ʿAbd Allah ibn Qurad al-Ziyadi, Shaddad ibn ʿUbayd Allah al-Qanani, and ʿAmr ibn ʿAbd Allah al-Dhibabi.

When they arrived before the Messenger of Allah ﷺ and he saw them, he said, “Who are these people who look like the men of India?” They said, “Messenger of Allah, they are the Banu al-Harith ibn Kaʿb.” When they stood before him, they greeted him with salām and said, “We bear witness that you are the Messenger of Allah and that there is no deity but Allah.” He replied, “And I bear witness that there is no deity but Allah and that I am the Messenger of Allah.”

He then said, “Are you the ones who, when rebuked, surge forward?” They remained silent; none of them answered. He repeated it a second and a third time, and still they did not reply. When he said it the fourth time, Yazid ibn ʿAbd al-Madan said, “Yes, Messenger of Allah, we are the ones who, when rebuked, surge forward,” and he said it four times.

The Messenger of Allah ﷺ then said, “Had Khalid not written to me that you had accepted Islam and had not been fought, I would have cast your heads beneath my feet.”

Yazid ibn ʿAbd al-Madan replied, “By Allah, we praised neither you nor Khalid.” He asked, “Then whom did you praise?” They said, “We praised Allah, Who has guided us through you, Messenger of Allah.” He said, “You have spoken the truth.”

He then asked, “By what means did you prevail over those who fought you in the time of ignorance?” They answered, “We did not prevail over anyone.” He said, “Indeed you did prevail over those who fought you.” They replied, “We used to prevail over our enemies because we would remain united and never divide, and we never initiated injustice against anyone.” He said, “You have spoken the truth.”

He then appointed Qays ibn al-Husayn as their leader.