Satan is recorded in the Bible as the original first intelligent creation to sin, and the perfecter of organized sin; he is an art and science of the craft of sinful misconduct. Sin is in effect, being lawless in the Creator's eyes; to be lawless, one must first break the law; however, Satan turned lawlessness into an art, and as it spread like a virus to mankind, and then to the holy angelic hosts that broke law, its existence became a thing of common acceptance; but is it really acceptable, or is it (the art of sin) merely being tolerated for a reason that will eventually climax in the future? And if so, will sin still be possible after Satan and his confederates bite the dust for the final round against the Creator?
The answer is yes, at least the practiced art of sin will not, but sin will be possible; to become an art, it first had to be cultured to a high degree, such as Satan has cultured sinful traits over the past centuries. But when Satan and all other past and present rebels of the Creator's laws are finally dealt with and removed from existence, there will be the possibility of sin being committed in the Kingdom of Christ Jesus; the possibility throughout eternity.
This is because of "free will" that's bestowed upon all of our Father's intelligent creations that are in His image; however, the perfecting of, and the organizing of sin into an art and science will no longer be tolerated at that time; instead, the offender will be immediately dealt with; they will be at a state of perfection in Father's eyes at that time, and no salvation will exist or be extended to them for breaking the Creator's law and thereby becoming lawless in Father's eyes.
The purpose of the Millennial Rule is to teach those that are of good heart, and willing to accept the truth as it really is, the laws that will have to be followed throughout eternity; of course, if you manage to get into the Kingdom, but you have a change of heart and do not accept the laws early on, you will perish for eternity; and, if after the Millennium, you have a change of heart when Satan and his demons are awakened and turned loose for a final test of trying to recreate organized sin among the Kingdom survivors, you will go down in defeat with him and his confederates. After that final execution, organized sin will have been eliminated; the art of sin, which is the practice of sin, it will no longer be tolerated; if you sin against Law after that period of time, you will be immediately exterminated and no longer in existence. The record on the practice of sin will have been completed; it is non-workable, therefore it is not acceptable to go outside of Father's Will and set up practice as a sinner like the Devil did along with his confederates.