Worth a watch. It's based within a concentration camp during WW2 where the prisoners put God on trial, with a mixture of Jews and non-Jews who debate not just the existence of God but his motives and any of his potential powers. God is determined to be guilty and when the time comes where they are brought to the gas chamber.. What do they do? They pray. Because they had nothing else they could possibly do, even though some believed God did not exist and if he did then he was actually a cruel, evil being, they prayed because they had no explanation for what was happening.
That's what I was on about when I was speaking about it filling gaps. If you want to fill the gap with simething specific then that is up to you, but I feel that many historically have believed in God (and still do now) because there is no other explanation. They didn't believe in God and yet still they prayed for his forgiveness.. Why? Because they had no other choice.