Jundub told of his hearing the Prophet say, “Those who preceded you used to take the graves of their prophets and righteous men as mosques, but you must not take graves as mosques; I forbid you to do that.”
‘A’isha told of God's Messenger as saying in his illness from which he did not recover, “God curse the Jews and Christians! They have taken the graves of their prophets as mosques.”
Ibn ‘Umar reported God’s Messenger as saying, “Perform some of your prayer in your houses, and do not turn them into graves.”*
* This is most probably a figurative expression indicating that a house in which prayer is not offered is like a grave, as God is not worshipped there.
Abu Huraira reported God’s Messenger as saying, “When one of you gets up for prayer he must not spit in front, of him, because he is holding intimate converse with God as long as he is in his place of prayer; nor must he spit towards his right, for there is an angel at his right; but he may spit towards his left or under his feet and bury it.” The version of Abu Sa'id has “under his left foot.”