Musannaf Ibn Abi Shaybah 34509 — Bilal (may Allah be pleased with him)

Mansur (may Allah have mercy on him) said that Mujahid (may Allah have mercy on him) said: The first to make Islam known were seven people: the Messenger of Allah (peace and blessings be upon him), Sayyiduna Abu Bakr (may Allah be pleased with him), Sayyiduna Bilal (may Allah be pleased with him), Sayyiduna Khabbab (may Allah be pleased with him), Sayyiduna Suhayb (may Allah be pleased with him), Sayyiduna Ammar (may Allah be pleased with him), and Sayyidah Sumayyah (may Allah be pleased with her), the mother of Sayyiduna Ammar (may Allah be pleased with him). As for the Messenger of Allah (peace and blessings be upon him), his uncle protected him, and as for Sayyiduna Abu Bakr (may Allah be pleased with him), his people protected him. All the others were seized, and then the disbelievers clothed them in coats of iron armour and left them in the scorching heat of the sun, until every one of them had to endure the utmost hardship, so they gave them everything they asked for. Then the people of each one of those men would bring water in large leather sheets, throw them into it, and then lift them up by the sides. The exception was Sayyiduna Bilal (may Allah be pleased with him): the disbelievers put a rope around his neck and then ordered the boys to drag him between the two mountains of Makkah. Even in that state he (may Allah be pleased with him) kept saying: "Ahad, Ahad," Allah is One.