While giving da'wah to a leader of Banu Amir ibn Sa'sa'ah, the Prophet ﷺ offered to show him a miracle. At his invitation, the chieftain called out to a small date palm in a nearby grove to come to him, and the sahabi narrating the account says the tree crawled all the way until it stood before him. The Prophet ﷺ then told it to go back, and it returned to its place. The chieftain accepted Islam on the spot.
After the chieftain Abu Bara Amir ibn Malik guaranteed protection for Muslim preachers in Najd, the Prophet ﷺ sent 70 of the best reciters and worshippers, mostly of the Ahl al-Suffa. Their messenger Haram ibn Milhan was treacherously killed by the arrogant chieftain Amir ibn al-Tufayl, who then rallied the tribes of Asiya, Ra'l, and Dhakwan (roughly 400-500 men) and massacred the 70 at the Well of Bir Ma'una. Only Ka'b ibn Zayd (left for dead beneath the bodies of the shuhada), Amr ibn Umayyah, and al-Mundhir ibn Muhammad were not killed outright in the initial attack; al-Mundhir chose to go back in and was killed, while Amr was freed and, on his way home, unknowingly killed two men under the Prophet ﷺ's protection before bringing the news to Madinah. According to one report the Prophet ﷺ learned of this and of al-Raji on the same night, and grieved so greatly that he prayed qunut against the four tribes responsible (Asiya, Ra'l, Dhakwan, and Banu Lahyan) in every prayer for a month.
Banu Amir ibn Sa'sa'ah, the tribe responsible for the Massacre of Bir Ma'una [see episode 51], sent a delegation to Madinah probably in the 7th or 8th year of the Hijrah, before the Conquest of Makkah. Among them came Amir ibn al-Tufayl, one of the massacre's chief instigators, with no intention of embracing Islam. He arranged with his henchman Arbad ibn Qays to assassinate the Prophet ﷺ with a poisoned dagger during a private audience, on a secret signal. The Prophet ﷺ refused Amir a private audience unless he embraced Islam. Amir tried repeatedly and gave the signal three times, but Arbad never acted; he later explained he could only ever see Amir, never the Prophet ﷺ, whenever the signal was given. When it became clear the plot had failed, Amir offered the Prophet ﷺ three options: split leadership of the towns and the Bedouins between them, be named his successor, or face an army of a thousand camels. The Prophet ﷺ refused all three and prayed against him. Amir fell fatally ill on the journey home while lodging at a prostitute's house; realizing he was dying, he fled on his horse into the darkness rather than die there, and was never seen again. Arbad returned to his own tribe and spoke impiously of Allah; the next day he and his camel were struck dead by lightning in front of his people. It is said Qur'an 13:11-13 refers to his fate.