What is the ruling on repeatedly shaking hands and raising one's voice when entering the mosque, before and after prayer, and upon finishing it, and what is the ruling if it interrupts a worshiper's remembrance of Allah or supplication?

Initiating greetings and shaking hands are religiously encouraged. However, it is disliked to initiate a greeting to someone reciting the Quran, or engaged in remembrance (dhikr) or supplication (du'a), as it distracts them from what they are doing. Greeting and shaking hands after prayer or before it, while standing in rows, distracts worshipers. It is also not appropriate to raise one's voice with greetings in the mosque, as it disturbs those praying and remembering God. Shaking hands immediately after prayer is not a Sunnah; rather, it is an innovation (bid'ah).