For as by one man's disobedience many were made sinners, so by the obedience of one shall many be made righteous. Rom. 5:19.
The method by which we live the Christian life is the same method by which we began it--by faith alone. Our justification is by faith alone--our acceptance with God is based totally on our receiving the merits of Jesus in our behalf. And we are to live by faith, as well.
One of the first reasons why obedience has to come by faith only is because of the nature of sin and sinners. We are all sinners, whether we have ever done anything "wrong" or not. It is not sinning that makes us sinners. It is getting born that makes us sinners. "For as by one man's disobedience many were made sinners, so by the obedience of one shall many be made righteous" (Rom. 5:19). We are sinners because we are born in this world of sin, and whether we ever sin or not is beside the point. We are sinners. "Our hearts are evil, and we cannot change them."--Steps to Christ, p. 18.
There are many texts that remind us of this fact. "There is none righteous, no, not one" (Chap. 3:10). "If we say that we have no sin, we deceive ourselves" (1 John 1:18). We are "by nature the children of wrath" (Eph. 2:3). "I know that in me (that is, in my flesh,) dwelleth no good thing" (Rom. 7:18). We are all sinners, and were all born sinners.
Perhaps the clearest passage on this subject is found in John 3. Christ tells us that in order even to see the kingdom of God, we must be born again. If this is true, then there had to be something wrong with our first birth. All of us who are born into this world are born with a problem--we are born sinners. We would remain so forever had it not been for the cross. But because of the cross, we do not have to remain separated from God. God gives every person the option of being born again.
The reason for studying this point in connection with the subject of obedience is this: If our hearts are evil and we cannot change them, then how could we ever obey? If in our flesh dwells no good thing, then how could we ever obey? We can't! It is only as we come to Jesus, admitting our helplessness, and accepting Him by faith, that we are put right with God.