If a Christian does not have to sin (I John 3:4-10), why does he? If we are new people, saints, perfect, then why the exhortations to “be perfect”? or – If our old, sinful self died with Christ, why (Col 2:20-3:17) are we told to “put to death” our sins and even “put on” the new man?
The simplest answer is to say, Be what your are; like telling a man, “Act like a man.” (That is why, though every Christian is “filled with the spirit” he is told to “Be filled with the Spirit” – that is, know Who you are; act out what God has put in.) Another answer: Just as our bodies are not the real “us”(though they die, we are still alive), the real you, the new you, does not commit those sins that trouble us so. Paul even goes so far as to say, “If I do what I do not want to do (sin), it is no longer I (the new me) myself who does it, but it is sin living in me.” Rms 7:7.
For illustration, think of a new computer, perfect, it makes no mistakes. But if I put or program wrong information into it, it will produce lies, mistakes. After our conversion we are like perfect computers, but we have been programmed so long with bad “software” (input) that after our conversion we still react, respond, the way we were used to. (Most of our 20,000 responses per day to our environment – other people, Satan – are “unconscious”, second nature.) You never have more than one self (new or old) at a time, but the death-struggles, the momentum, the grave-clothes of the old nature (software) have to be gotten rid of. This is what we usually think of as “sanctification”, the improvement of our souls – minds, emotions, will – although we – our spirit – is sanctified, perfect, Spirit-filled, from Day One. “Christ is our sanctification” – not sanctifier – though he is that too, just as he is our complete justification. I Cor 1:30. I john 4:13,15,17b. I Cor 6:17.
New Question: Doesn’t that make a Christian “easy” on sin and his own sins? To the contrary; a person who realizes that he does not have to sin, feels all the more guilty when he does. What is more, he has an increasing awareness of what sin is; he is much harder on himself as to what is wrong. Eg, he does not limit it to obvious things like lying or stealing, but wasting time (doing nothing) is sin. So is “religion” instead of godliness. (“I desire mercy, not sacrifice.”) But he thanks God for the forgiveness of those once-unrecognized sins, puts them behind him, and grows spirituality by means of the whole experience. (Any one who has a low view of sin is not a Christian. Rms 6:1-7)
That answers the question as to why God “punishes” the Christian for his sins (reaps the results of) as well as the unbeliever. In the case of the Christian the failure becomes a sanctifying experience, from which God makes good to come. It would be a terrible calamity for a believer if – just because his sins have all been paid for and it is not really “he” that does them – he could sin with impunity. The “clear conscience” that a Christian has is from knowing he is guilt-free; his conscience is increasingly sharp as to what sin is and what it deserves.
What about the “Lord’s Prayer” and “Forgive us our debts”? 1. At best, this is a “baby-Christian’s” prayer, intended as a model (for people who did not know how to pray), not to be used as a substitute for our own. It might even be called a “birth-cry” prayer, a “sinner’s prayer”, marking his conversion as he asks for forgiveness and putting God first instead of self. (Cf Luke 11s:13; Acts 2:38 – so Calvin) 2. It is certainly an Old Testament prayer, in a class with those of David (“Take not thy Holy Spirit from me.”) It is not in Jesus’ name (John 16:24). Atonement for sin was still unmade; the “Kingdom” had not yet come. (NB: The New Testament begins with Acts, not Matthew; the Old begins with Exodus, not Genesis 1 or 3.) This explains the spiritual immaturity of most Christians. When you think that Christmas and Good Friday/Easter are all in the Old Testament, most of their knowledge of salvation has to do with the ABC’s of the faith. (Cf. John 14:26; 16:25; 15:12; Matt. 11:11; Hebs 5:11-6:3) This is the weakness in using the Decalog primarily as a Guide to Gratitude.
What about “Lead us not into temptation”? This, too, is Old Testament. James 1, I Peter 1:6 say we should welcome, rejoice in trials; Jesus himself did not pray to keep Peter from them. (Luke 22:31) What we do ask is victory, and God has promised us that . Plus the guarantee that even our failures will have constructive purposes. Luke 22:31; John 21:15-19.