سنن أبي داود

Abu Sa’id al-khudri said: The Prophet(ﷺ) liked the twigs of the date-palm, and he often had one of them in his hand. He entered the mosque and saw phlegm in the wall towards qiblah and he scraped it. He then turned towards people in anger and said: Is any one of you is pleased to spit in his face? When any of you faces qiblah, he indeed faces his Lord, the Majestic the Glorious: the angels are at right side. Therefore, he should not spit on his right side or before him towards qiblah. He should spit towards his left side or beneath his foot. If he is in a hurry, he should do so-and-so. Describing it Ibn ‘Ajlan said: He should spit in his cloth and fold a part of it over the other.