What do you usually think of when you hear the word "confession"? Many people think first of the definition that has a negative connotation—being forced to admit you have done something wrong. But when we agree with God's Word by "confessing" it out loud, the result is always positive.
An acquaintance of mine says we cannot defeat Goliath with our mouths shut. When David was preparing to do battle with the giant Goliath, he ran toward him, confessing out loud what he believed the end result of the battle would be: "This day the Lord will deliver you into my hand... "(1 Sam. 17:46 AMP).
This is a good example of how we should approach the enemies in our own lives. We must open our mouths and speak the Word of God.
I strongly encourage you to confess the Word of God out loud daily. Each time a thought comes to your mind that does not agree with God's Word, confess the truth of His Word out loud, and you will find that the power of the Word will overcome the lie.