I was reading yesterday in Matthew 13:24-30 when Jesus told the parable of the weeds. In verse 25 it said "But while his men were sleeping, his enemy came and sowed tares (weeds) among the wheat, and went away."
This was one of those wake-up calls from God to me. I get so frustrated when I allow satan to get into my head and try to convince me of his lies. This verse reminded me that satan can only do that when I allow him to - when I am "sleeping", he can plant weeds in my mind. When I get more focused on myself than God, I am "sleeping" spiritually - that's the best time for satan to attack.
Stay awake! Don't give satan the chance.