God is perfecting a cadre of leaders, the body of Christ, that will rule and reign with Jesus Christ for 1000 years, Re 20:4&6. And Satan plays an important role in all of this..

1 Peter 5:8-12 KJVS
Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour: [9] Whom resist stedfast in the faith, knowing that the same afflictions are accomplished in your brethren that are in the world. [10] But the God of all grace, who hath called us unto his eternal glory by Christ Jesus, after that ye have suffered a while, make you perfect, stablish, strengthen, settle you. [11] To him be glory and dominion for ever and ever. Amen. [12] By Silvanus, a faithful brother unto you, as I suppose, I have written briefly, exhorting, and testifying that this is the true grace of God wherein ye stand.

That word accomplished in verse 9, has the same meaning as a person who is an accomplished pianist?. One who is well practiced.

Hebrews 5:12-14 KJVS
For when for the time ye ought to be teachers, ye have need that one teach you again which be the first principles of the oracles of God; and are become such as have need of milk, and not of strong meat. [13] For every one that useth milk is unskilful in the word of righteousness: for he is a babe. [14] But strong meat belongeth to them that are of full age, even those who by reason of use have their senses exercised to discern both good and evil.

That word exercised appears later in the book of Hebrews.

Hebrews 12:6-11,29 KJVS
For whom the Lord loveth he chasteneth, and scourgeth every son whom he receiveth. [7] If ye endure chastening, God dealeth with you as with sons; for what son is he whom the father chasteneth not? [8] But if ye be without chastisement, whereof all are partakers, then are ye bastards, and not sons. [9] Furthermore we have had fathers of our flesh which corrected us, and we gave them reverence: shall we not much rather be in subjection unto the Father of spirits, and live? [10] For they verily for a few days chastened us after their own pleasure; but he for our profit, that we might be partakers of his holiness. [11] Now no chastening for the present seemeth to be joyous, but grievous: nevertheless afterward it yieldeth the peaceable fruit of righteousness unto them which are exercised thereby. [29] For our God is a consuming fire.

Luke 3:16-17 KJVS
John answered, saying unto them all, I indeed baptize you with water; but one mightier than I cometh, the latchet of whose shoes I am not worthy to unloose: he shall baptize you with the Holy Ghost and with fire: [17] Whose fan is in his hand, and he will throughly purge his floor, and will gather the wheat into his garner; but the chaff he will burn with fire unquenchable.

The chaff is the flesh and will be burned on the sin sacrifice altar, without the camp.

Hebrews 13:8-14 KJVS
Jesus Christ the same yesterday, and to day, and for ever. [9] Be not carried about with divers and strange doctrines. For it is a good thing that the heart be established with grace; not with meats, which have not profited them that have been occupied therein. [10] We have an altar, whereof they have no right to eat which serve the tabernacle. [11] For the bodies of those beasts, whose blood is brought into the sanctuary by the high priest for sin, are burned without the camp. [12] Wherefore Jesus also, that he might sanctify the people with his own blood, suffered without the gate. [13] Let us go forth therefore unto him without the camp, bearing his reproach. [14] For here have we no continuing city, but we seek one to come.

The fire of that altar is suffering.

1 Peter 4:1-2,12-13 KJVS
Forasmuch then as Christ hath suffered for us in the flesh, arm yourselves likewise with the same mind: for he that hath suffered in the flesh hath ceased from sin; [2] That he no longer should live the rest of his time in the flesh to the lusts of men, but to the will of God. [12] Beloved, think it not strange concerning the fiery trial which is to try you, as though some strange thing happened unto you: [13] But rejoice, inasmuch as ye are partakers of Christ’s sufferings; that, when his glory shall be revealed, ye may be glad also with exceeding joy.

All of this will continue until…

Revelation 12:9-11 KJVS
And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him. [10] And I heard a loud voice saying in heaven, Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: for the accuser of our brethren is cast down, which accused them before our God day and night. [11] And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death.