Sunan Abi Dawud 477
سنن أبي داود#477SahihAbu Hurairah reported:The Messenger of Allah(ﷺ) said: if anyone enters the mosque, and spits in it, or ejects phlegm, he should remove some earth and bury it there. If he does not do so, then he should spit in his clothes and not come out with it
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniHasan Sahih
Muhammad Muhyi Al-Din Abdul HamidHasan Sahih
Shuaib Al ArnautHasan
Zubair Ali ZaiIsnaad Hasan
In-book reference: 2:87