I don't think I could ever single out just one verse to declare it my favorite but I Thessalonians 2:13 certainly has to be ONE of my favorites. "And for this reason we also constantly thank God that when you received from us the word of God's message, you accepted it not as the word of men, but for what it really is, the word of God, which also performs its work in you who believe."
That one little phrase "performs its work in you who believe" is what makes it a treasure to me. The Greek word for "performs its work" is "energeo", meaning active and energetic, accomplishing action, proving strong. We get our word "energy" from it. This is what God's Word does in us - it is active (living and active, Hebrews 4:12 tells us) in our lives, not static. It is always at work in us, accomplishing what God wants to do in us. God calls the process "sanctification". Making saints out of sinners :) Transforming us. Working our salvation out from our spirit to our behavior. Changing how we think, how we act, how we feel, who we are.
So, how do we tap into this energy? This active and accomplishing power? Can we just "claim" a few lines from the Bible each day and expect God to work His magic? Recite a bunch of verses from time to time and watch ourselves turn into superheroes? Not. That's where the remainder of the phrase comes in. "in you who believe" . God's Word does indeed perform its work.....in you who believe.
What is belief? Faith. And what is faith? Mental assent? God says "By faith, Abraham...obeyed" in Hebrews 11:8. So, "you who believe" means "you who obey". Because if we believe what God's Word says, we will obey it. And when we obey it, we are demonstrating faith. And faith pleases God. In fact, without it, it is impossible to please God. And it is His pleasure that works in us to transform us.
If I want to see more of God's energy, power, transformation in my life, I need to get His Word in me. To read it regularly. To meditate on it. Memorize it. Treasure it. And then I need to believe it. Obey it. Live by it. Arrange my life around it.
And watch it perform its work.