1 Peter 5:8 says” Be sober, be vigilant; because your adversary the devil walks about like a roaring lion, seeking whom he may devour.
The whole design of Satan is to devour and destroy souls. He always is contriving whom he may ensnare to eternal ruin.
Our duty plainly is, to be sober; to govern both the outward and the inward man by the rules of temperance. To be vigilant; suspicious of constant danger from this spiritual enemy, watchful and diligent to prevent his designs.
He cannot touch those who are kept by the power of God through faith unto salvation; but he walketh about, looking eagerly after any lost sheep that may have wandered from the fold. He roars in the craving of his heart for prey, like a hungry lion, seeking whom he may devour.
Each one of us should check ourselves to see if we have wandered away from the fold.