I don't mind too much but just FYI that's actually a pretty unpleasant thing to say.
a) It's very disrespectful to all the non-believers who've died defending your right to practice whatever religion you choose without interference.
b) The implication that non-believers are really just hypocrites who, when under stress will suddenly have a change of heart is unjustified and arrogant.
I mention this because I've found people using this phrase who haven't really considered the implications they're making and how someone who doesn't share their beliefs will perceive them.
The point of the expression, in my mind, has less to do with religion than it does with expressing the point that under extreme circumstances people's most dearly held perspective can change.
For the record, I'm an atheist, OK?