The Muslim should respect the mosques and keep them free of dirt and impurities, and anything that is not appropriate, and he should bear in mind that he is conversing with his Lord in His house. In this hadith, the Prophet (blessings and peace of Allah be upon him) says: When one of you stands in prayer, then he is conversing with his Lord. This is affirming that Allah (may He be exalted) is close to His slave who is praying. What is meant is that the worshipper should bear in mind when praying that Allah is close to him, and that He can see him and hear him, and that he is conversing with Him; He hears what he says, and He responds to his conversing with Him. Therefore the Prophet (blessings and peace of Allah be upon him) told the worshipper not to spit in front of him, or to his right. If he cannot help but spit, then let him spit to his left, because his devil-companion stands on his left when he is praying, or let him spit beneath his feet, then cover it by burying it in the ground, if the place where he is praying is not carpeted and has an earthen floor. But if the place where he is praying is carpeted, then he should spit into the edge of his garment and the like, as is mentioned in al-Sahihayn in the hadith of Anas ibn Malik (may Allah be pleased with him). Spitting in the mosque is a sin, because it is indicative of disrespect towards the houses of Allah (may He be glorified in exalted) which He has commanded are to be built and His name mentioned therein. Moreover, it is offensive to other worshippers. A worshipper may prostrate on it without realizing, and he may be disgusted if he sees it and find it repugnant..