Think about when you made a lot of effort to look for something that wasn't missing. Think about how you felt when you were making frantic efforts to find something, only to realize that you had been holding that thing in your hands all the while. How did you feel? Embarrassed? Think about the effort. Think about the diligence that you put in not knowing it had been in your hands. 

When we speak about righteousness, there are two kinds. There's the one you try with your effort to produce and there's one that you receive as a gift; God's righteousness. 

Picture trying to attain by effort, something that you can receive freely as a gift of grace. Sadly when it comes to righteousness, the trophy does not go to those who put in the work, it goes to those who believe and receive.