"The Messenger of Allah ﷺ said: 'Spitting in the Masjid is a sin, and its expiation is to bury it.'"  

قَالَ رَسُولُ اللَّهِ ﷺ الْبُصَاقُ فِي الْمَسْجِدِ خَطِيئَةٌ وَكَفَّارَتُهَا دَفْنُهَا