Luke 4:13 - "When the devil had finished every temptation, he left Him until an opportune time."
And that's really what the devil's all about, isn't it? He's nothing but an opportunist, with all the negative connotations that word entails. Like the disease-ridden mosquito that waits for the opportune moment to strike, to steal away your life blood, small, almost imperceptible amounts at a time, so is the enemy. He lurks, never putting himself at risk, watching, waiting until an opportunity presents itself, and then he strikes.
But I place my hope in the Lord God Almighty. I will not fear. I will be wise to the devil's workings, but I will not fear him.