moving

Assalamualaykum waRahmtullah,Please can you tell me if it is ‘essential’ to move the lips in salah or is it OK to pray in the mind. If a person prefers to pray in the mind will his prayer be valid or not? Is there a sin in praying in the mind? Also, if it is essential to pray by moving the lips does this relate to both recitation of the Quran as well as when saying words such as Allahu Akbar, Sami Allahulimanhamidah and so on?Thank you for your help, Wassalam.

As-Salamu `alaykum. I want to know whether a person’s Prayer—salah—will be valid or not if he recites the Qur'an or takbir without moving the lips. He is only reading or saying the takbir in his mind or heart. Is his Prayer invalid? In fact, I surveyed the Net and read some fatwas on this issue, but all of them say that if a person reads only in his heart or mind without moving his lips, his Prayer will be invalid. However, I myself find this ruling so hard since a person may not move his lips and still maintain khushu` (concentration in Prayer) and reflect on what he says in his heart or mind. Is the superficial moving of the lips, along with reading the Qur'an, an integral part of the salah, or is what matters attentive reading of the Qur'an and dhikr? Jazakum Allahu khayran.