It is narrated from Sayyiduna Anas bin Malik, may Allah be pleased with him, that the Noble Prophet, peace and blessings be upon him, said: When any one of you is in prayer, he is whispering to his Lord, so no person should spit to his right side. The words of Ibn Ja'far's narration are: He should not spit in front of him or to his right side, but should spit to his left side or beneath his feet.

It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: Spitting in the mosque is an evil, and burying it is a good deed.

Abu Sa‘d says that I saw Sayyiduna Wathilah bin Asqa‘ (may Allah be pleased with him) praying in the mosque of Damascus. He spat under his left foot and rubbed it with his foot. When he finished, I said: "You are among the companions of the Messenger of Allah (peace and blessings be upon him), and you are spitting in the mosque?" So Sayyiduna Wathilah (may Allah be pleased with him) replied that he had seen the Messenger of Allah (peace and blessings be upon him) doing the same.

Sayyiduna Abu Sahla Sa’ib bin Khallad رضي الله عنه narrates that a man was leading the people in prayer while the Messenger of Allah صلى الله عليه وآله وسلم was watching him. During the prayer, he spat in the direction of the qiblah. When he finished, the Messenger of Allah صلى الله عليه وآله وسلم said: This person should not lead you in prayer again. Later, when he intended to lead the prayer, the people stopped him and informed him of the statement of the Messenger of Allah صلى الله عليه وآله وسلم. He mentioned this to the Messenger of Allah صلى الله عليه وآله وسلم, and he صلى الله عليه وآله وسلم said to him: Yes, (I forbade you) because you have offended Allah Almighty.

It is narrated from Sayyiduna Abu Dharr (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: My Ummah was presented before me with their good and bad deeds. Among their good deeds, I saw the removal of something harmful from the road, and among their bad deeds, I saw spitting phlegm in the mosque without burying it.

Sayyiduna Tariq bin Abdullah narrates that the Noble Prophet (peace and blessings be upon him) said: When you pray, do not spit in front of you or to your right side; rather, spit to your left side, provided it is empty (i.e., there is no worshipper praying on that side). Otherwise, lift your foot and (spit beneath it and) rub it in.

Sayyiduna Umar bin Khattab (may Allah be pleased with him) said in one of his sermons: O people! You eat two plants, garlic and onion; I consider them to be foul (disliked). By Allah! I saw the Noble Prophet (peace and blessings be upon him), whenever he sensed their smell from someone, he would order such that the person’s hand would be taken and he would be led out of the mosque, until he was brought to the Baqi’ place. If anyone must eat them, then he should cook them to eliminate their odor.

It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: Whoever eats this plant (onion or garlic), let him not come to the houses of Allah (i.e., the mosques).

It is narrated from Sayyiduna Abu Hurairah, may Allah be pleased with him, that the Messenger of Allah, peace and blessings be upon him, said: Whoever eats from this tree, that is, garlic, should by no means come to our mosque and cause us harm. In another place, he said: Such a person should neither come near our mosque nor harm us with the smell of garlic.

Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) says: We had not gone beyond the conquest of Khaybar when we entered a field of greens, and the people were hungry, so we ate a lot of it. Then we went to the mosque, and when the Messenger of Allah (peace and blessings be upon him) perceived the smell, he said: Whoever has eaten from this foul (unpleasant) tree should not come near us in the mosque. The people began to say: It has become forbidden, it has become forbidden. When this news reached the Messenger of Allah (peace and blessings be upon him), he said: O people! I have no authority to make unlawful what Allah has made lawful. In reality, it is a tree whose smell I dislike.