Jo said: "Regarding 1Jo 5:18, I would say John is talking about willfully sinning in a grievious manner, not the smaller sins of our daily lives. I admit that John is not very clear on this issue in this epistle - first, he admits we all sin, then he says that those who sin are of the devil. A minor sin, one that John would not consider "deadly", would not turn the man to evil, so perhaps this is what John is discussing.
This is a confusing verse. It looks like Jo's thinking is along the lines of Matthew Henry. Here is what he said: (Kolo, I pinged you re: our "demon discussion")
"Here we have,
I. A recapitulation of the privileges and advantages of sound Christian believers. 1. They are secured against sin, against the fulness of its dominion or the fulness of its guilt: We know that whosoever is born of God (and the believer in Christ is born of God, v. 1) sinneth not (v. 18), sinneth not with that fulness of heart and spirit that the unregenerate do (as was said ch. iii. 6, 9), and consequently not with that fulness of guilt that attends the sins of others; and so he is secured against that sin which is unavoidably unto death, or which infallibly binds the sinner over unto the wages of eternal death; the new nature, and the inhabitation of the divine Spirit thereby, prevent the admission of such unpardonable sin.
2. They are fortified against the devil's destructive attempts: He that is begotten of God keepeth himself, that is, is enabled to guard himself, and the wicked one toucheth him not (v. 18), that is, that the wicked one may not touch him, namely, to death. It seems not to be barely a narration of the duty or the practice of the regenerate; but an indication of their power by virtue of their regeneration.
They are thereby prepared and principled against the fatal touches, the sting, of the wicked one; he touches not their souls, to infuse his venom there as he does in others, or to expel that regenerative principle which is an antidote to his poison, or to induce them to that sin which by the gospel constitution conveys an indissoluble obligation to eternal death. He may prevail too far with them, to draw them to some acts of sin; but it seems to be the design of the apostle to assert that their regeneration secures them from such assaults of the devil as will bring them into the same case and actual condemnation with the devil.
FK, your conclusion runs up against 2100 years of scriptural exegesis by The Church. You know, I really think it comes down to those differing understandings of theosis. For us, once one attains theosis, which as I have said is extremely rare in this mortal state, one would be completely safe, but until then one wouldn't be.
I suspect I sound like a broken record, but how could the God bearing Fathers who put the canon of the NT together be so, so wrong in this absolutely vital area? Every single Father, except perhaps +Augustine and arguably Origen (who was condemned for a teaching something like what you are proposing though a bit broader), agrees on this. Much of the Protestant sola scriptura mentality seems founded in a reaction against Rome, the medieval structure and theology of which many extend back in time to at least the Emperor Constantine. In a way I don't blame the Protestants for doing this since if one listened only to Rome for most of the past 600 years one would think that the Church looked like the Church of Alexander VI right back to the Apostles. But that simply isn't true as both history and the writings of the Fathers amply demonstrate. I don't doubt that that is a hard mentality to overcome, but if you desire to understand, if not accept, the theology of The Church on theosis, you have to take off two pairs of glasses; one that of Protestantism and the second a very old medieval Roman pair. I am not suggesting that you will then ipso facto become Orthodox. I am suggesting that you will recognize the innovation which the Reformers wrought. At that point, having compared that innovation with what The Church had uniformly believed up to that point, you can determine if in fact God did something entirely new and innovative through the Reformers.