Be alert and of sober mind. Your enemy the devil prowls around like a roaring lion looking for someone to devour. (NIV)

Be well balanced (temperate, sober of mind), be vigilant and cautious at all times; for that enemy of yours, the devil, roams around like a lion roaring [in fierce hunger], seeking someone to seize upon and devour. (AMP)

Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour: (KJV)