There are those who say that we evidently can’t change, that we’ll be essentially the same over the years not overcoming certain sins. Now I’m talking about Christians and I don’t think they mean that at conversion we aren’t set on a new path. I think the path they mean is one in which there needs to be daily confession to God for sin and I agree with that. But it also includes the “wretched man” syndrome of Romans 7 (a misinterpretation of that passage in its own context and in light of Romans 6 and 8) in which under the law (not under grace) we do what we don’t want to do and what we want to do we don’t.
There is no question that sin can be and often is a struggle for us in this life. We have arrayed against us the world, the flesh and the devil. At certain points we will be sorely tempted and tested (depending on the perspective) and will feel weak. At other times grace will seem to carry us. But the fact is by grace in and through Jesus by the Spirit we are to live and grow in God’s will. We are to live out our baptism into Christ as those who have died and are dead to sin and who are alive to God and to righteousness. On that basis not letting sin reign over us (Romans 6). By the Spirit fulfilling the requirement of the law, putting to death the deeds of the flesh (Romans 8).
We have to let scripture speak, even if it doesn’t fit into our theology. Our theology needs to be adjusted to scripture, not scripture to our theology. I think here too of the gospels. Jesus doesn’t suggest a halfway house in which we live between conversion and kingdom come. You gouge out the eye and cut off the hand. You take up the cross and follow. You do as he commands.
If we believe we can’t turn the corner in regard to sin, then it makes it less likely we will. Moses was once a person who took matters in his own hands, but we are told that he became the most humble person on the face of earth. Some might argue that he simply grew up and matured. In part that’s surely the case. But didn’t he have to turn the corner on the sin of pride which arguably is thinking of and looking to ourselves and not thinking of and looking to God?
Yes, if scripture (not a “pietist strain”) can be taken at face value, while we will struggle in this life, we can turn the corner on sins. We won’t be sinless in this life; we won’t reach final perfection. But by God’s grace in and through Jesus and by the Spirit we can change. We can leave what is sinful behind as we instead learn to do God’s will in Jesus. Involving a process to be sure. But we in and through Jesus can and therefore should do it.