A story goes like this....
Once there was a drought and people of the city decided to gather at the local temple and pray for rain. Almost everyone from the town came, but only one child came with an umbrella!
Such is the faith! Do we have it?
Often we resolve to think positive. For example, I will win the lottery today. Yet, when we go to the store, we buy the cheapest ticket, so as to not 'lose' a lot of money. We are again not thinking of gaining. And, as the luck eventually proves that it was on our side, we repent, we should have invested more, may be a bigger prize would have been ours!
We don't even believe in ourselves. We do not need any proof of being us. How can we even think of having faith in God whose existence we are not even sure of?