Shu’bah said: I asked Qatadah,“Did you hear Anas (may Allah be pleased with him) narrate from the Messenger of Allah (peace and blessings be upon him) that spitting in the mosque is a sin?”Qatadah said:“Yes, and (I also heard that) its expiation is to bury it.”

It is narrated from Sayyiduna Anas (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When a servant stands to pray, he is whispering (in intimate conversation) with his Lord," or he said, "His Lord is between him and the qiblah. So if any of you is compelled to spit, let him spit to his left or under his foot or do like this," and he (the Prophet) spat in his garment and folded its edge and rubbed it.

Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said: The Noble Prophet (peace and blessings be upon him) was delivering a sermon when, during this, he saw phlegm on the wall towards the qiblah side of the mosque. He became angry at the people present in the mosque and said: "When any one of you is in prayer, Allah, Glorious and Exalted, is in front of him." (Khatabi and others said: Allah's mercy or Allah's qiblah is in front of him.) "Therefore, he must never spit in front of himself," or he said, "nor blow his nose in front of himself." Then he ordered, and that spot was scraped off, or he ordered and it was wiped over. Hammad said: I do not know anything except that he said it was wiped over with saffron.

Sayyiduna Abu Sa'id Khudri and Sayyiduna Abu Hurairah (may Allah be pleased with them both) reported that the Messenger of Allah (peace and blessings of Allah be upon him) saw phlegm on the wall of the (Prophet's) Mosque, so he scraped it off with a pebble. Then the Messenger of Allah (peace and blessings of Allah be upon him) said: "When any of you spits (during prayer), he should not spit in front of him nor to his right side, but rather to his left side or under his foot."