Will a sign from God will convince us of his existence?

[tommynba]

That depends on what kind of "sign". If it's a chips in a shape of Mary or Jesus probably not.

I had a dream once that i was waiting for a bus... and i actually had to wait for a bus that day. That just proves we dream about the things that had happened or are likely to happen in the near future, even though we're not conscious of it, and then we attribute magic meaning to the simple things.