“for I forbid you to do that.” (1)
Taking graves as places of worship means praying beside them, even if no structure has been erected there, for every spot deliberately chosen for prayer becomes a mosque. The Prophet—may Allah bless him and grant him peace—said: “The entire earth has been made for me a mosque and a purifier.” (2) If a mosque is actually built over a grave, the violation is even graver.
Most people have contravened these prohibitions and fallen into what the Prophet—may Allah bless him and grant him peace—warned against, thereby committing major shirk. They have built mosques, mausoleums, and shrines upon graves and turned them into pilgrimage sites where all forms of major idolatry are practiced: slaughtering animals for the graves, calling upon those buried there, seeking their aid, dedicating vows to them, and so forth. The eminent scholar Ibn al-Qayyim (may Allah have mercy on him) said: “Whoever compares the Prophet’s sunnah concerning graves—his commands, his prohibitions, and the practice of his Companions—with what most people do today (3) will find the two diametrically opposed and mutually contradictory; they can never be reconciled.”