The Word of God tells us that Satan prowls like a roaring lion seeking whom he may devour. He wants to devour your faith, peace, joy, and rest. He has no authority over you so he will "study" you to see what makes you tick. In case you didn't know, he plays the "long game". He will wait and in the most opportune time plant a lie here or a distraction there. What "study material" are you giving him with the way you think, live, speak, behave, react, and interact with others?