Satan also knows us well. But the way he knows us is different from the way God knows us. God knows us because he knows everything.
One of the most famous kings over the Hebrew people in Old Testament times was a man named David. He also wrote many of the psalms. In one of them he states, “O Lord, you have searched me and you know me. You know when I sit and when I rise; you perceive my thoughts from afar. You discern my going out and my lying down; you are familiar with all my ways. Before a word is on my tongue, you know it completely, O Lord.”
What David said about God is not something we could say about Satan. He is not everywhere at once as God is. Nor can he read all of our thoughts as God can.
But the devil has spent a lot of time studying us. He knows our habits, even our sinful ones. That puts him in a good position to tempt us. For he knows that some things will be more tempting for us than others.
For example, some people are tempted by money. They may steal money from a coworker, roommate, or relative. That is their weakness. So the devil does what he can to place these temptations before them.
This was true for a disciple of Jesus called Judas. This man loved money, so the devil tempted him to negotiate with the Jewish leaders to betray Jesus. In exchange he would be paid a good sum of money. He fell for the temptation and sold his friend for a bag of cash.
What are your pet sins? What are some of the sinful things that tempt you? Gossip? Evil thoughts? Internet porn? Material stuff? Popularity? Sex? To a certain extent we all have different weaknesses. And the devil knows that.
The good thing is that God also knows our weaknesses. Instead of tempting us to sin, God promises to help us avoid temptation. That’s what a line in the Lord’s Prayer is all about: “But lead us not into temptation.” When we pray those words, we are asking that God would help us avoid or overcome temptation. We know that he has the power to help us. For Jesus resisted the devil’s temptation three times in the wilderness (See Matthew 4) and many times after that.
It’s kind of scary to think that the devil knows our weaknesses. But think of it—Jesus knows them, too. And he has promised to help us overcome them.