Volume 1, Book 8, Number 409:
Narrated Anas:
The Prophet saw expectoration (on the wall of the mosque) in the direction of the Qibla and
scraped it off with his hand. It seemed that he disliked it and the sign of disgust was apparent from
his face. He said, “If anyone of you stands for the prayer, he is speaking in private to his Lord, (or) his
Lord is between him and his Qibla, therefore he should not spit towards his Qibla, but he could spit
either on his left or under his foot.” Then he took the corner of his sheet and spat in it, folded it and
said, “Or do like this.”