Musannaf Ibn Abi Shaybah

Hazrat Zir, may Allah have mercy on him, narrates that Hazrat Abdullah bin Masood, may Allah be pleased with him, said: The first seven persons to openly declare Islam were: the Messenger of Allah, Hazrat Abu Bakr, Hazrat Ammar, may Allah be pleased with him, and his mother Hazrat Sumayyah, may Allah be pleased with her, Hazrat Suhaib, Hazrat Bilal, and Hazrat Miqdad, may Allah be pleased with them. In any case, Allah protected the Messenger of Allah, peace and blessings be upon him, through his uncle Abu Talib. And Allah protected Abu Bakr, may Allah be pleased with him, through his people. And the rest were seized by the Quraysh. They were made to wear iron armor and were thrown into the heat of the sun. There was none among them except that they yielded before their (the Quraysh's) intentions, except Hazrat Bilal, may Allah be pleased with him. He considered himself insignificant for the sake of Allah, and became easy for the people. So they seized him and handed him over to the children, and the children would drag him through the streets of Mecca while he kept calling out, "Ahad, Ahad" (Allah is One, Allah is One).