Haram bin Milhan (r.a.)
Four months after the Battle of Uhud, Abu Bara, the leader of Sons of Amir living in the region of Najd, came to the Prophet and asked him to send some Companions to his tribe to teach Islam. After receiving a guarantee from Abu Bara that he would protect the Companions he would send, the Messenger of Allah sent a delegate of guides consisting of 40 people (according to a narration, 70 people) from Suffa School. One of the people in this delegation was Haram bin Milhan.
Hz. Haram was the maternal uncle of Hz. Anas bin Malik. He was also the brother of Umm Sulaym and Umm Haram. He took part in the Battles of Badr and Uhud, and fought heroically. He read the Quran with a beautiful voice. His rhetoric was also good.
After the preparations, the delegates set off. Abu Bara set off before them and told the people on the way that the Companions of the Messenger of Allah were under his guarantee and warned them not to harm them. Meanwhile, the group of guides reached Mauna Well. They stopped and had a rest there. They asked one another, “Who will invite the people living around to Islam?” Hz. Haram said, “I will.” Then, he said to his friends, “Stay where you are until some news reaches you from me. If they allow me to convey them the order the Messenger of Allah gave us, it is all right. If they do not allow and if they act treacherously, you are not away from me. You will take measures.”
When Haram bin Milhan approached them, he said, “Will you allow me to convey you the message of the Messenger of Allah?” When they did, he invited them to Islam. “I am the envoy the Messenger of Allah sent you. I witness that there is no god but Allah. Muhammad is His slave and Messenger. Believe in Allah and His Messenger.”
Then, he delivered the letter sent by the Messenger of Allah to Amir b. Tufayl. Amir did not even bother to read the letter. He signaled to one of his men, who speared Haram bin Milhan from behind. The spear pierced his body and came out from the front. Hz. Haram said, “Allahu akbar! I swear by the Lord of the Kaaba that I have won.” He reached the high degree of martyrdom.
After Haram bin Milhan, the polytheists martyred the other Companions too. They released only Amr bin Umayya. Before being martyred, the Companions said, “O Lord! There is nobody except You who can inform Your Messenger about us. Send our greetings to him. O Lord! Inform our tribe through Your Messenger that we joined our Lord. We are pleased with our Lord and our Lord is pleased with us.”
The Prophet (pbuh) was in Madinah then. Jibril arrived and conveyed their greetings to him. The Prophet told his Companions about them as follows:
“Your brothers confronted the polytheists. The polytheists slayed them and threw spears at them. When they were martyred, they said, ‘O Lord! Inform our tribe that we are pleased with our Lord and our Lord is pleased with us.’ Ask forgiveness from Allah for them. They sent greetings to me.”
Then, the Prophet (pbuh) prayed against those murderers. Due to his prayer, the cruel polytheists were hit by drought and famine. They were destroyed. 
Tabaqat, 3: 514; Usdul-Ghaba, 1: 395; Mustadrak, 2: 110-111.