Q 2: What is the ruling on
a person who enters the Masjid (mosque) while the Imam (the one who leads congregational Prayer) is giving the Khutbah (sermon) and greets the people?
Should they return his greeting? I heard His Eminence Shaykh
Al-Musnad saying, "Whoever enters the Masjid should not talk, ask anybody to sit here, or ask anybody to be silent while the Imam is giving the Khutbah."
It is impermissible for a person who enters the Masjid while the Imam is giving the Khutbah to greet the people sitting in the Masjid, and they should not return his greeting either. However, it is permissible to return the greeting by signs. It is also impermissible to ask anybody to sit down or keep quiet if he is listening to the Khutbah. The original ruling on this is the saying (Part No. 8; Page No. 244) of the Prophet (peace be upon him),
If you even ask your companion to be quiet on Friday while the Imam is delivering the Khutbah, you have in fact talked irrelevance.
Muslim and others.
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.