One might think that, when a person becomes aware that he is sinning, or of the seriousness of a past sin, that he would want to correct himself and pursue new obedience.

I’m not talking about people who don’t believe that their sins are sins. A person may know he is a philanderer but boast in it rather than being ashamed of it.  Such people are not “aware” in the sense that I mean it.

What I mean is that person who is aware that he is a philanderer may in fact wallow in the sin once it comes home to him that he has committed it.

Rather than seeing the odiousness of sin as an incentive to avoid it, people tend to see the odiousness of sin as a reason to believe that there is no point in obeying. They have already blown it. Nothing they do can change the past so there is no point in trying to change. (Some groups who traffic in sins make a point of recruiting by getting a prospect to commit a serious sin so that he or she will forget about ever going back to their former way of life.)

That’s why it is important to remember that grace precedes obedience.  God did not give the Ten Commandments to Israel as a way to get out of Egypt, but only after he had already declared that they were His children and had already liberated them from Egypt.

Q. 101. What is the preface to the Ten Commandments?
A. The preface to the Ten Commandments is contained in these words, I am the LORD thy God, which have brought thee out of the land of Egypt, out of the house of bondage. Wherein God manifesteth his sovereignty, as being JEHOVAH, the eternal, immutable, and almighty God; having his being in and of himself, and giving being to all his words and works: and that he is a God in covenant, as with Israel of old, so with all his people; who, as he brought them out of their bondage in Egypt, so he delivereth us from our spiritual thraldom; and that therefore we are bound to take him for our God alone, and to keep all his commandments (Westminster Larger Catechism).

Likewise, when God calls on people to repent, the call presupposes that God loves the sinner and is waiting to accept him.  It is true the Prodigal Son managed to return without realizing this but one point of Jesus’ parable was to tell people that God was indeed waiting–longing for sinners to repent. As the Westminster Confession puts it (ch 15), repentance is not possible with only a recognition of the evil of sin, but also requires an understanding of God’s mercy:

By it, a sinner, out of the sight and sense not only of the danger, but also of the filthiness and odiousness of his sins, as contrary to the holy nature, and righteous law of God; and upon the apprehension of his mercy in Christ to such as are penitent, so grieves for, and hates his sins, as to turn from them all unto God, purposing and endeavoring to walk with him in all the ways of his commandments.

Without grace and a promise of mercy, awareness of sin only leads to despair and more sin.