One of the lucky people that the Prophet saved from slavery, included among the most honorable people and regarded as of Ahl al-Bayt is Hz. Thawban (r.a.).
Hz. Thawban was from Yemen. He was sold as a slave in the market. The Prophet paid the necessary money and bought him. Then, he freed Thawban. However, Thawban warmed to the Messenger of Allah, who was a vast ocean of compassion, all of a sudden. He did not want to leave the Prophet. Noticing this, the Prophet made him the following offer:
“Return to your family and live with them if you wish. Or, stay with us here with Ahl al-Bayt.”
This was an offer that Thawban wanted very much. He decided to stay with the Messenger of Allah without thinking.
Thus, Hz. Thawban attained the honor of serving the family of the Prophet. He was also the special servant of the Prophet. He was a clever, shrewd and intelligent person. He fulfilled every order of the prophet and did his duties perfectly.
Hz. Thawban narrates one of his reminiscences about the Prophet as follows:
When the Messenger of Allah (pbuh) went on a journey, the last member of his family he saw was Fatima; when he returned, he would visit Fatima first. Once, he returned from an expedition. Hz. Fatima had hung up a cloth on her door. Hasan and Husayn had two silver bracelets on their arms. When the Prophet saw them, he went past her house without entering. Hz. Fatima understood that the Messenger of Allah did not enter her house because of the cloth she had hung up on the door. She removed the cloth, unfastened the bracelets from the boys, put them in their hands and sent them to their grandfather. Hasan and Husayn went to the Messenger of Allah crying. The Messenger of Allah took the bracelets and said to me,
“O Thawban! Take them to so and so family. Buy a necklace made of knucklebone for Fatima and two bracelets made of ivory. They are my Ahl al-Bayt. I do not like it when they have the boons of Paradise in this world.”
Hz. Thawban respected the Prophet a lot and never tolerated any disrespect toward him; he would react suddenly. He sometimes had trouble due to this severe loyalty.
Once, a Jew came and wanted to talk to the Messenger of Allah (pbuh). He addressed the Prophet as “Assalamu alayka ya Muhammad!” When Hz. Thawban heard the Jew address the Prophet with his name, he reprimanded him, "Why did you not say O Messenger of Allah?" Then, he started to fight with the Jew. He hurt the Jew. Thawban said, "I regard addressing the Messenger of Allah only with his name as a mistake." The Messenger of Allah calmed Thawban down and said, "My name is Muhammad in my family."
Hz. Thawban, was a lover of the Prophet who could not put up with being separated from him. He sometimes remained away from the Prophet due to some duties. Once, he came to the presence of the Messenger of Allah in a terrible state. His face was pale, his body was weak and there was an expression of sorrow in his face.
When the Prophet saw him like that, he asked him, "O Thawban! What has happened? Are you ill? Thawban replied as follows:
"O Messenger of Allah! I am not ill nor have I any pain. When we come to your presence, we look at your face, sit next to you and listen to you. When I do not see you, my love toward you increases; I feel grievous until I rejoin you. Then, I remember the hereafter and fear that I will not be able to see you there. For, you will be in a higher station with the prophets in Paradise and I will be in a lower position. I am worried that I will not be able to see you there." 
The Prophet listened to Hz. Thawban and was about to answer him when Jibril came and read the following verse:
“All who obey Allah and the Messenger are in the company of those on whom is the Grace of Allah― of the Prophets (who teach) the sincere (lovers of Truth), the witnesses (who testify), and the Righteous (who do good): ah! How a beautiful fellowship!”
When the revelation was completed, Hz. Thawban was so happy. He felt like a child due to his happiness. He received the reward of his love toward the Messenger of Allah in the world; he also received the glad tiding of seeing his blessed face in Paradise.
Once, the Prophet addressed his Companions as follows:
“If somebody promises me about something, I will promise him Paradise.”
Thereupon, Hz. Thawban acted very quickly and said, “I will.” The Prophet said to him, “Do not ask anything from anybody; do not ask questions!”
After that, Thawban did not ask anything from anybody. When his whip fell while he was riding, he would not ask it from anybody; he would get off and pick it up himself. 
Hz. Thawban served the Prophet until the Prophet died. He sacrificed his whole life for the Prophet. He was lucky enough to receive its reward in the world. He deserved Paradise as it is mentioned in the hadith above and he was regarded among Ahl al-Bayt.
The Prophet was praying for his family while Thawban was there. Thawban said, “O Messenger of Allah! I am of Ahl al-Bayt.” When he repeated it three times, the Prophet accepted it and said, “Yes, you are of us too as long as you do not go to the door of anyone and ask anything from anyone.” For, to ask sadaqah from others and to be indebted to someone was something that did not fit Ahl al-Bayt.
When Hz. Thawban heard that he was regarded as one of the members of Ahl al-Bayt, he became very happy. He acted in accordance with this advice of the Prophet throughout his life.
Hz. Thawban memorized the hadiths he heard from the Prophet when he was with him and kept them in his memory. Thanks to this, he became a hadith scholar. There are 127 narrations of Thawban in hadith books. He educated several students in hadith. He also had a deep knowledge of Islamic law.
When the Prophet died, Hz. Thawban could stay in Madinah only for three days. Wherever he looked, he remembered the Prophet. He could not put up with his separation. He left Madinah like Bilal al-Habashi. He went to the region of Damascus and settled in Ramla. Then, he took part in the conquest of Egypt. He spent the last days of his life in Homs. He died in the 54th year of the Migration.
May Allah be pleased with him!
One of the hadiths Hz. Thawban narrated is as follows:
"Imminently, there will come a time when the nations gather against you, just as people gather around a feast." We said, "O Messenger of Allah! Will it be because we are few at that time?"
The Prophet said, "No, you will be numerous in those times, but you will be as useless as the scum of the sea. Allah will remove the fear that your enemies used to posses from you from their hearts and He will place wahn in your hearts."
We said, "What is wahn?"
The Messenger of Allah said, "Love of life and hatred of death."
 Usd al-Ghaba, 1: 249.
 Musnad, 5: 275; Abu Davud, Tarajjul: 21.
 Mukhtasar Tafsir Ibn Kathir, 1: 411; Asbab an-Nuzul, p. 158-159.
 an-Nisa, 69.
 Asr-ı Saadet, 3: 387; Mustadrak, 5: 481.
 Musnad, 5: 277.
 Isaba, 1: 204.
 Tajrid Translation 4: 64.
 Musnad, 5: 278; Abu Dawud, Malahim: 5.