Michael Horton uses the following story to illustrate how Christ has paid our debt of sin and credited us with his righteousness:

After my junior year in college, I went to Europe with some friends. Having misjudged my expenses by several digits, I phoned home for help. My parents transferred money from their account to cover outstanding bills and included an additional sum from which I could draw until the end of the trip.

Now, was this money, which I was going to draw daily as I needed, strictly speaking, my money? No, it belonged to my parents; nevertheless, because they had transferred it to my account, it was my money. My account was now filled with money I had not earned but which was mine to use nonetheless.