(His shrine is found in Sa’i al-Bahr Street immediately in front of al-Rawda island)
He is the Sharif Abu Abdullah Mohammed, the son of al-Husayn, the son of Hamza, the son of ‘Ubayd Allah al-A’raj, the son of al-Husayn the junior, the son of ‘Ali Zayn al-Abidin, the son of Imam al-Husayn, the Prophet’sﷺ grandson. He was nicknamed Sa’i al-Bahr and Abu al-Shafaqa.
Mohammed Ibn al-Husayn was a pious God-fearing man known for his righteousness. He was nicknamed Sa’i al-Bahr because Egypt faced thirst and hunger due to low flooding. Mohammed Ibn al-Husayn would walk along the Nile’s bank and weep due to his extreme compassion and affection for the people. He would supplicate Allah for the Nile to flood and it is for this reason that he was known as Abu al-Shafaqa (the father of compassion).
al-Sakhawy mentioned in Tuhfat al-Ahbab that Mohammed Ibn al-Hasan was intent upon finding the letter that the Leader of the Believers, ‘Umar Ibn al-Khattab, had sent to the Nile. He persisted in his mission, asking the people of knowledge and historians about it until he found it. This was because he had seen ‘Umar in a dream instructing him to throw the letter in the Nile. Mohammed Ibn Abu al-Hasan followed ‘Umar’s instructions and that year was the most fertile for the people of Egypt.
The letter read as following:
From the servant of Allah, the Leader of the Believers, to the Nile of Egypt. To proceed:
If you flow of your own will, then cease to do so. And if you flow by the will of Allah, the One and Only, the Omnipotent, then we ask Allah the One and Only, the Omnipotent, the Almighty, to cause you to flood.
When Mohammed Ibn al-Husayn died 330 AH , he was buried near the sea as the Egyptians called the Nile.