I understand that when praying Zuhr and Asr prayer the Sura's have to be recited silently, but what does it actually mean? Is it a whisper that one must be able to hear or is it sufficient to just move the lips and not completely hear the recitation?
Reciting Quran in Zuhr and Asr Prayers must be with Ekhfaat which means with low voice which can be heard by you in usual cases. It is like whispering with out clear voice. Just moving the lips with out hearing anything is not enough in Ekhfaat.
Wassalam.