Huzayma bin Thabit (r.a.)
Every member of the luminous generation of the Companions, who lived a life of Paradise in the world by attaining the honor of listening to the luminous talks of the Messenger of Allah, has an aspect that sheds light on us, a phase of life that is a model for us and wise statements that guide us. However, we cannot know all of the life of the Companions who were together with the Prophet for a long time who did not leave him alone in the mosque, city and battlefields. Tabaqat and siyar books give information of a few lines about some Companions and mention only one or two famous incidents of others. Some of those incidents may seem simple at first sight but they are important and luminous since a prophet that receives revelation is included in them.
Huzayma bin Thabit, who was one of the notables of Ansar, was a distinguished person who was with the Prophet all the time in Madinah and who was loyal to him. He was a person who helped to spread Islam and settle it in the hearts with both his knowledge and sword. He never showed any weakness in his perseverance and resolution, enthusiasm and loyalty from the time he became a believer just before the Migration to his death. He fought in the same rank as the believers in all battles including the Battle of Badr. He was the standard-bearer of his tribe during the Conquest of Makkah. He was so hostile to polytheism and idolatry that the Prophet gave the duty of breaking the idols of Sons Khatma to him. 
Hz. Huzayma bin Thabit became famous with the nickname, “Dhush-Shahadatayn” (Having two witnessings). That is, his witnessing was worth the witnessing of two people. He was given this nickname after the following incident:
The Prophet once bought a horse from a Bedouin called “Sawa bin Qays” and was taking him to his home to pay him. The Prophet hurried to go home and the Bedouin followed him with the horse. Some people who saw the horse the Bedouin was holding approached him and asked him whether the horse was for sale. When the Bedouin said it was, they offered him a price. This price was much more than the price the Prophet offered. This extra amount was enough to cause the Bedouin to change his mind. He called out to the Prophet who was ahead:
“If you want to take this horse, take it; otherwise I will sell it to somebody else.”
When the Prophet heard his voice, he turned around and said, “Have I not already bought it from you?”
The Bedouin began to deny it: “By Allah I have not sold it to you yet.”
The Prophet insisted: “You know that I have bought it from you.”
Upon this argument, some people gathered. They wondered what the attitude of the Prophet (pbuh) would be. The Bedouin continued to speak: “Bring me two witnesses that I have sold this horse to you and I will agree.”
This time, the Companions intervened because the man crossed the line. They said, “Woe on you! The Prophet (pbuh) does not tell anything other than the truth. Whatever he says is true.” However, the Bedouin insisted on witnesses. The Prophet could not bring a witness because there was nobody with them during the deal.
Just then, Huzayma came forth. He said to the Bedouin,
“I am a witness that you sold this horse to the Messenger of Allah (pbuh).”
The Prophet turned toward Huzayma and said, “O Huzayma! How can you be a witness? You were not with us when we made the deal.”
“O Messenger of Allah! I approve you because of the truths that you introduced. I definitely know that you tell nothing but the truth.”
The Prophet became very pleased with the courage and loyalty of Huzayma and said,
“Whenever Huzayma bears witness, his witnessing is regarded the same as the witnessing of two people.”
Thus, the Prophet regarded him the same as two reliable individuals.” 
The Companions reached such a high rank in loyalty that they believed in that lofty person that they loved sincerely without hesitation and searching. Due to this surrendering, they became successful in everything.
One night, Hz. Huzayma saw the Prophet (pbuh) in his dream. He kissed the Prophet on the forehead. He became very happy due to this dream; he told the Prophet about his dream in the morning. The Prophet was talking to the Companions; he said, “O Huzayma! Your dream is true.” He called him bowed his head and asked him to kiss his forehead. Hz. Huzayma, became very excited; he felt as if he was flying. He approached the Prophet and attained the honor of kissing the luminous forehead of the Prophet. 
Hz. Huzayma, who did great service to Islam during the caliphate of Hz. Abu Bakr, Umar and Uthman was martyred in Siffin when he was in the army of Hz. Ali.
May Allah be pleased with him!
Usdul-Ghaba, 2: 114.
Musnad, 5: 215-216.
ibid, 5: 215.