R. C. Sproul, considering the separation between God and man that made a substitutionary atonement by a God-man necessary, draws three circles. The first represents the character of man.
Imagine a circle that represents the character of mankind. Now imagine that if someone sins, a spot—a moral blemish of sorts—appears in the circle, marring the character of man. If another sin occurs, more blemishes appear in the circle. Well, if sin continues to multiply, eventually the entire circle will be filled with spots and blemishes. . . . Human character is clearly tainted by sin . . . The sinful pollution and corruption of fallen man is complete, rendering us totally corrupt. . . .
To take it further, when the apostle Paul elaborates on this fallen human condition, he says, “‘There is none righteous, no, not one; . . . There is none who does good; no, not one’” (Rom. 3:10b-12). That’s a radical statement. Paul is saying that man never, ever does a good deed, but that flies in the face of our experience. When we look around us, we see numerous people who are not Christians doing things that we would applaud for their virtue. . . . But how can there be these deeds of apparent goodness when the Bible says that no one does good?
The reason for this problem is that when the Bible describes goodness or badness, it looks at it from two distinct perspectives. First, there is the measuring rod of the law, which evaluates the external performance of human beings. For example, if the law says you are not allowed to steal, and you go your whole life without stealing, we could say that you have a good record. You’ve kept the law externally.
But in addition to the external measuring rod, there is also the consideration of the heart, the internal motivation for our behavior. We’re told that man judges by outward appearances, but God looks on the heart. From a biblical perspective, to do a good deed in the fullest sense requires not only that the deed conform outwardly to the standards of God’s law, but that it proceed from a heart that loves Him and wants to honor Him. You remember the great commandment: “‘You shall love the Lord your God with all your heart, with all your soul, and with all your mind’” (Matt. 22:37). Is there anyone reading this book who has loved God with all of his or her heart for the past five minutes? No. Nobody loves God with all of his heart, not to mention his soul or mind. . . .
If we consider human performance from this perspective, we can see why the apostle would come to his apparently radical conclusion that there is no one who does good, that there’s no goodness in the full sense of the word found among mankind. Even our finest works have a taint of sin mixed in. I have never done an act of charity, of sacrifice, or of heroism that came from a heart, a soul, and a mind that loved God completely.
—R. C. Sproul, The Truth of the Cross (Reformation Trust, 2007), 85, 87–89.