From Among the Good and Evil Deeds of People
Abu Dharr (radi Allahu anhu) reported that The Prophet (sal Allahu alaihi wa sallam) said, “The deeds of my people, good and bad, were presented before me, and I found the removal of harmful objects from the road among their good deeds, and phlegm which might be in a mosque left unburied among their evil deeds.”
Allah has listed in virtue even the good deed which is for the benefit of people or can save them from loss. What is its opposite, however small it may be, is reckoned as mischief. This Hadith induces one to do good deeds to attain the Pleasure of Allah and prevents one from evil deeds so that one is saved from the displeasure of Allah.
The Hadith enjoins cleanliness of mosques and forbids throwing of anything there which violates its sacredness, i.e., spitting. If any such dirty thing is found there, it must be removed immediately.
And Allah Knows Best!