The Masājid (مساجد) are sincere places of worship that should be visited only for the worship of Allāh, and for no other reason. Not only this, but the correct etiquettes must also be followed.
In this concise yet beneficial article I will include some etiquettes that must be followed in the Masājid:
As something that is actually ḥarām, one must stay completly silent during the Khuṭbah so that everyone will be free of distraction and be completely focused on the Khuṭbah, so that they may benefit completely from it.
Abū Hurairah (رضي الله عنه) reported:
"The Prophet ﷺ said, 'If you tell your companion to be quiet on Friday while the Imam is speaking, you have spoken improperly.'" (1)
Imām an-Nawawī (رحمه الله) said regarding this hadīth:
"In this tradition is the prohibition of every kind of talking during the Khuṭbah." (2)
One may reverse a spot for himself in the Masjid. This is something that should not be done, especially since this can lead to Riyā’ (show-off).
This can be excused however, such as the Imām, who obviously has his own spot reserved, and if one has to quickly leave and come back only for a need, like if he needs to make Wuḍūʾ.
If one were to give Salām to you while you are praying, you should respond with an Īshāra (notification by his hand).
In the Masjid, one should not announce that he has lost something, as the Masājid was not built for this purpose.
Abū Hurairah (رضي الله عنه) narrated that the Prophet (ﷺ) said:
"Whoever hears a person announcing a lost item in the Masjid then he should say, 'May Allāh not return it to you for verily the Masjid has not been built for this purpose.'" (3)
I ask Allāh to allow us to firmly act upon these etiquettes.
May Allāh bless you, and shukran.
Sources :
1. Ṣaḥīḥ al-Bukhārī 892, Ṣaḥīḥ Muslim 851, graded Muttafaqun Alayh
2. Sharḥ al-Nawawī ‘alá Ṣaḥīḥ Muslim 851
3. Ṣaḥīḥ Muslim 568