Be sober [well balanced and self-disciplined], be alert and cautious at all times. That enemy of yours, the devil, prowls around like a roaring lion [fiercely hungry], seeking someone to devour.
1 Peter 5:8
Sometimes we get complacent and comfortable and we forget that we have an enemy that is always near, waiting for the opportunity to catch us in our weakness and "devour" us. This is why it's so important to stay close to God and His word, the truth.
The Lord is on my side, I will not fear. What can [mere] man do to me?