Musannaf Ibn Abi Shaybah 34176 — Reports on the virtue of Umar bin

Zayd bin Wahb (may Allah have mercy on him) reports that two men came to Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him), and one of them said: "How do you recite this verse?" Sayyiduna Abdullah (may Allah be pleased with him) asked him: "Who taught you to recite this verse?" He said: "Abu Hakim al-Muzani." He asked the other: "Who taught you to recite this verse?" He said: "Sayyiduna Umar (may Allah be pleased with him) taught me." He said: "Recite as Sayyiduna Umar (may Allah be pleased with him) taught you." Then he wept until his tears fell upon the pebbles. Then he said: "Surely Sayyiduna Umar (may Allah be pleased with him) was a strong and firm fortress of Islam, which Islam entered and did not leave. When Sayyiduna Umar (may Allah be pleased with him) passed away, a breach opened in that fortress, so Islam went out of it and did not enter it."