The problem of the hidden God?
According to the Bible, when the Israelites wandered in the desert for forty years, God fed them by making food fall regularly from the sky.
Then the LORD said to Moses, "I will rain down bread from heaven for you. The people are to go out each day and gather enough for that day. In this way I will test them and see whether they will follow my instructions. (Exodus 16:4)
During the 1980's, several thousands Ethiopians died slowly and painfully from starvation due to a prolonged drought.
Ethiopians are mostly Christians. (over 60%)
http://en.wikipedia.org/wiki/Religion_in_Ethiopia
So, believers of God (Christians) died from starvation due to a prolonged drought in Ethiopia.
God had then the opportunity to make food fall from the sky for starving Ethiopians, as the Bible claims he did in the past, in order to prove his existence, his power and his love. But he did not rain down food from heaven for starving Ethiopians.
Non-Christians would say that God did not manifest his presence because he does not exist. Or at least he does not care his people.
@ Michael
But what about God does not care His People.
OK, God exists but He did not care His people (Ethiopians), although he did to Israelites.
@ Quaz
Do you mean "the discrimination of God between His believers"?