It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) asked a Bedouin: "Have you ever been struck by Umm Mildam (fever)?" He asked: What is Umm Mildam? He (peace and blessings be upon him) said: "It is a heat that lies between the skin and the flesh." He said: I have never experienced anything like that. He (peace and blessings be upon him) asked: "Have you ever had al-suda' (a headache)?" He asked: What is al-suda'? He (peace and blessings be upon him) said: "It is a vein that throbs in a person's head." He said: I have never had this either. When the man turned his back and left, the Messenger of Allah (peace and blessings be upon him) said: "Whoever would like to see what a man of the people of Hell is like, let him look at this man." This hadith is sahih (authentic) on the condition of Muslim, but the two Shaykhs did not record it.

Sayyidah Aishah (may Allah be pleased with her) narrates: I heard the Messenger of Allah (peace and blessings be upon him) saying: "Whenever a vein of a believer throbs (with pain), Allah forgives one of his sins in return for it, records a good deed for him, and raises him one rank." The chain of this hadith is sahih (authentic), but the two Shaykhs did not record it; and Imran bin Zayd al-Tha'labi is an elder (shaykh) from Kufah.