For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
Keri Anderson
I agree with Tim's answer. Also, I think it's a lack of prayer that is what makes us vulnerable. God is good and in control at all times :) We can trust Him. But this was a good question because I have wondered that before myself. So thanks both for the question and answer!
Danny Hickman
What if Satan hears your prayer? Satan can't stop God from doing anything; who cares if he knows what we talk to God about?