Musannaf Ibn Abi Shaybah 7758 — Sending blessings at the grave

Ma'rur bin Suwayd said: We set out with Sayyiduna Umar (may Allah be pleased with him) for a Hajj. In the Fajr prayer he recited Surah al-Fil and Surah Quraysh. When he had completed his Hajj and was returning, at a certain place the people rushed forward. Sayyiduna Umar asked: "What is here?" He was told: "This is the place where the Prophet (peace and blessings be upon him) prayed." He said: "It was because of this that the People of the Book were destroyed: they took the relics of their prophets as places of worship. What should be done is this: if the time of prayer comes upon you here, then pray; and if it does not, then do not pray."