Mukhtasar Bukhari

Narrated by Sayyiduna Hudhaifah bin Yaman (may Allah be pleased with him): (On one occasion) the Prophet Muhammad (peace and blessings be upon him) said: "Write down the names of all those who recite the Kalimah of Islam and bring them before me." So we wrote down the names of one thousand five hundred men. Then we thought to ourselves, should we still fear the disbelievers when we are one thousand five hundred men? But indeed, we found ourselves overcome by fear, to the extent that a man would pray alone out of fear.