When many people refer to 'their faith', they are actually referring to a mixture of faith and unbelief. (I have even heard Bishops make this error!)
If God is an opinion - then this is not faith. 'Faith' is actually a certainty.
'Lack of faith' has nothing to do with 'belief in God' in these circumstances but, is rather, about the outworking of faith.
For example, I know God exists from personal experience BUT do I have sufficient 'faith' to believe that 'He will move this particular mountain'?
We can refer to the former as 'saving faith'.
