You must move your lips at least.

I talk to Allah in my heart all the time. I find myself constantly making duah or saying things in my sleep like la ilaha ila Allah wahdahu la sharika lah, lahu al-mulk wa lahu al-hamd, wa huwa `ala kulli shay’in qadir – but this is all in my heart & my lips aren’t moving. Do u have to utter it with your lips to be rewarded or is this worship from the heart?

Supplications |