What was the noise?
Rashi: The bones were knocking on each other.
Malbim: The Ru'ach of revival came to the bones, and the bones came to the proper place.
Why does it say "va'Tikrevu"?
Radak: Over the course of time, the bones had separated from each other 1 .
Radak: "Va'Tikrevu" is feminine regarding the Tav, but not regarding the end; normally, feminine plural would be va'Tikrevenah. We find like this ? "v'Almenosayich Alai Tivtachu" (Yirmeyah 49:11). Usually, Etzem is feminine; "Al Atzmo" is masculine.
Why does it say "Etzem Al Atzmo"?
Rashi: The bones of each [Mes], wherever they were scattered, each jumped and came to where it connects [with the other bones].