Abbas bin Ubada (r.a.)
It was before the Migration... The Prophet (pbuh) sent Mus’ab bin Umayr, a young Companion, to Madinah so that he would spread Islam and teach the Muslims there. Hz. Mus’ab was a person who could speak well and could explain what he meant without offending people. Therefore, the Messenger of Allah sent him there with such an important duty. In fact, Hz. Mus’ab fulfilled this duty very well. He came to Aqabah with 75 people, 73 of whom were men and 2 of whom were women in the 13th year of the prophethood. He met the Prophet there.
One of those 75 people who went there in order to pay allegiance to the Prophet was Abbas bin Ubada. He could speak fluently. He made a very nice speech there:
“You will in fact avow that you will fight Arabs and non-Arabs. You will face many dangers. You may die, lose your property and be scattered. Pay allegiance if you want to take the risk. If you think of leaving the Messenger of Allah to the hands of the enemy, give this up now. If you promise and cannot keep your promise, it will be disgrace for you in both the world and the hereafter. If you protect him against all kinds of dangers, it will be good for you in both the world and the hereafter.”
Upon this speech, the people who were in Aqabah said all together,
“We are ready to face any danger to protect him.” Then, they paid allegiance to the Messenger of Allah one by one. This pleased the Messenger of Allah very much.
While the pledge continued at Aqabah, the polytheists were informed about it. The Prophet said to the Muslims of Madinah,
“Go back to the places where you stopped over.” Hz. Abbas bin Ubada spoke sincerely:
“O Messenger of Allah! We swear by Allah, who sent you with the true religion, we will attack the people in Mina and kill them if you give us permission.” However, the Prophet said,
“We were not ordered to do so yet.”
After the Pledge of Aqabah, Hz. Abbas settled in Makkah. He wanted to be near the Prophet. Meanwhile, the polytheists increased the torture and pressure on the Muslims. However, Hz. Abbas was ready to take any risks in order to be near the Prophet. As a matter of fact, when he was in Makkah, he encountered many problems. When the order to migrate was given, he migrated to Madinah. Thus, he received the honor of being both a Muhajir and an Ansar. He was given the name “the Muhajir of Ansar”. The Prophet established brotherhood between him and Osman bin Ma'zun, one of the notables of Muhajirs.
Hz. Abbas did not join the Battle of Badr because of his excuse. However, he suffered its agony. He was one of the first people to join the army the Prophet prepared for the Battle of Uhud. One of those who persevered when the army was defeated due to the disobedience of the archers for the order of the Messenger of Allah (pbuh) was Abbas. He swung his sword on the enemy and shouted as follows:
"O Muslims! This misfortune that you are suffering is the result of your disobedience to your Prophet. He promised you that you would be helped if you showed patience and perseverance. If we are not among those who protect the Messenger of Allah and if he is harmed, we will have no excuse to present to our Lord. "
Hz. Abbas broke the sheath of his sword after completing his speech. He took off his armor and helmet. He remained among the polytheists. Despite receiving many wounds, he tried to stand up and swing his sword at the enemy lest the polytheists should harm the Messenger of Allah. Finally, he was exhausted. He was martyred with the happiness of protecting the Messenger of Allah until he breathed his last. May Allah be pleased with him! 
Usdul-Ghaba, 3: 108-10; Sirah, 2: 90; Hz. Muhammed ve İslamiyet, 3: 154.