Psalm 119:29 Keep me from lying to myself; give me the privilege of knowing your instruction.
Wow! This says so much in so few words! I have always heard the worse lies we tell are the ones we tell ourselves. David knew that lying to himself would only cause him harm. He also knew that knowing God's word, God's truth would help him not lie to himself. Knowing God's word also helps us to not believe the lies that the world tells us or that Satan tells us.
The world tells us we need, need, need, God's word tells us that we only need God. The world can tell us we suffer many mental illnesses, God's word tells us that we are given a sound mind. Satan tells us we don't matter, God's word tells us that if God cares about the Lillie's of the field that .god cares even more for us. The world tells us that no one understands us, God's word tells us that He knitted us together in our mothers womb, which means God knows every part of our bodies and our minds. The list goes on and on. When we believe what the world says about us and what Satan says about us, we are lying to ourselves. David knew he needed to know the truth, that the truth would set him free of so many things and set him on the right track. It also sets us free when we believe what God says about us. remember God is the author of truth. When we believe the good God says about us, our lives begin to change in amazing ways!