Explanation of the words of Imam al-Nawawi (may Allah have mercy on him) regarding what he quoted: "

The Shaykh : In the name of Allah, the Most Gracious, the Most Merciful.
The author (may Allah have mercy on him) stated, in what he quoted from Abu Dharr (may Allah be pleased with him), that the Prophet (peace and blessings be upon him) said: And the One who made them clear to him is Allah (Mighty and Majestic), for Allah (Glorified and Exalted is He) is the One who makes things lawful and forbidden and makes things obligatory. So Allah (Mighty and Majestic) showed our Prophet Muhammad (peace and blessings be upon him) the good and the evil of the Ummah’s deeds.
He found among their good deeds “the removal of harm,” meaning the removal of that which causes harm to passersby, such as thorns, sticks, stones, glass, dung, and other things. Everything that causes harm, its removal is among the best of deeds. The Prophet (peace and blessings be upon him) clarified that removing harm from the path is charity, so it is among the best of deeds and carries the reward of charity. The Prophet (peace and blessings be upon him) also clarified that faith has seventy-odd branches, the highest of which is saying “La ilaha illa Allah” (There is no god but Allah), and the lowest of which is removing harm from the path, and modesty is a branch of faith. So if you find harm on the path and you remove it, then that is among the best of your deeds, it is charity for you, and it is among the characteristics and branches of faith. And if this is among the good deeds and among the charities, then placing harm in the path of the Muslims is among the worst of deeds. These people who throw peels—watermelon peels, orange peels, banana peels, or others—into the markets and in the paths of people, there is no doubt that if they harm the Muslims, they will be sinned against. Allah the Exalted said: The scholars said: “If an animal or a person slips on it and breaks, then the one who placed it is liable for compensation”. He is liable for blood money or less than blood money if it does not amount to blood money. The important thing is that this is a harm to the Muslims.
Also included in this is what some people do of pouring water in the markets, which harms people. Cars may pass by it and splash it onto a person’s clothes. And there is no doubt that it causes damage to the asphalt, for whenever water comes to the asphalt repeatedly, it melts and becomes damaged. The important thing is that, unfortunately, we are a Muslim Ummah and we do not care about these matters, as if they are nothing. A person throws harm in the markets and does not care about it. He breaks bottles in the markets and does not care about it. He throws sticks and does not care about it. He places a stone and does not care about it. So it is recommended for us, whenever we see something that causes harm, to remove it from the path, for that is charity and among the best of deeds.
Then he said: “Among the worst deeds” “is phlegm,” meaning the phlegm. It is called that because it comes from the marrow. Phlegm in the mosque is not buried. It is not buried because the mosque in the time of the Messenger (peace and blessings be upon him) was paved with gravel, with small pebbles, so the phlegm was buried in the earth. But with us now, there is no earth, but if you find it, you should scrape it with a handkerchief until it is gone.
Know that phlegm in the mosque is forbidden. So whoever spits in the mosque has committed a sin, due to the saying of the Prophet (peace and blessings be upon him): So the Prophet (peace and blessings be upon him) established that it is a sin, and its expiation is burying it. Meaning, if a person did it and wanted to repent, let him bury it. But in our time, let him scrape it with a handkerchief or something similar until it is removed. And if this phlegm is so, what about what is greater than it? Some people sometimes, and although it is rare now because there is no animal dung in the markets, but people in the past would enter with their shoes without checking them or turning them over, so there would be dung in them, and the dung would fall from the shoe into the mosque, polluting it. So consider the phlegm and what is like it in harming the mosque or greater than it.
Also included in this is that some people have these light handkerchiefs with them, they spit in them, and then throw them on the ground in the mosque. This is no doubt a harm, for souls are disgusted when they see such a thing. How much more so if that is in one of the houses of Allah? If you spit in a handkerchief, put it in your pocket or in a hidden place until you go out and throw it in the market, on the condition that you do not harm anyone. And success is from Allah.