Evil Must Be Permitted to Come to Maturity

God in His wisdom permitted Satan to carry forward his work, until the spirit of disaffection ripened into active revolt. It was necessary for his plans to be fully developed, that their true nature and tendency might be seen by all. Lucifer, as the anointed cherub, had been highly exalted; he was greatly loved by the heavenly beings, and his influence over them was strong. God's government included not only the inhabitants of heaven, but of all the worlds that He had created; and Satan thought that if he could carry the angels of heaven with him in rebellion, he could carry also the other worlds. He had artfully presented his side of the question, employing sophistry and fraud to secure his objects. His power to deceive was very great, and by disguising himself in a cloak of falsehood he had gained an advantage. Even the loyal angels could not fully discern his character or see to what his work was leading. — {GC 497.1} (PP 41.2)

In the councils of heaven it was decided that principles must be acted upon that would not at once destroy Satan's power; for it was God's purpose to place things upon an eternal basis of security. Time must be given for Satan to develop the principles which were the foundation of his government. The heavenly universe must see worked out the principles which Satan declared to be superior to God's principles. God's order must be contrasted with Satan's order. The corrupting principles of Satan's rule must be revealed. The principles of righteousness expressed in God's law must be demonstrated as unchangeable, perfect, eternal. — {RH, September 7, 1897}

In heaven Satan was next to the Son of God. But he yielded to the desire for self-exaltation, and was expelled from the heavenly courts. He came to this earth, to exercise over man his debasing power. This power increased with the ages, but its evil was not recognized, and God could not arbitrarily condemn its author. Satan's work was a deadly peril to the universe, but for the security of the world and of the government of heaven, he must be allowed to develop his principles in their true light. — {YI April 16, 1903, par. 3} 

Even when it was decided that he could no longer remain in heaven, Infinite Wisdom did not destroy Satan. Since the service of love can alone be acceptable to God, the allegiance of His creatures must rest upon a conviction of His justice and benevolence. The inhabitants of heaven and of other worlds, being unprepared to comprehend the nature or consequences of sin, could not then have seen the justice and mercy of God in the destruction of Satan. Had he been immediately blotted from existence, they would have served God from fear rather than from love. The influence of the deceiver would not have been fully destroyed, nor would the spirit of rebellion have been utterly eradicated. Evil must be permitted to come to maturity. For the good of the entire universe through ceaseless ages Satan must more fully develop his principles, that his charges against the divine government might be seen in their true light by all created beings, that the justice and mercy of God and the immutability of His law might forever be placed beyond all question. — {GC 498.3} (PP 42.3)

His (Satan’s) crooked course must be allowed to continue until he should reveal himself as an accuser, a deceiver, a liar, and a murderer. In the latter act, Satan uprooted himself from the affection of the loyal universe. In the death of the Son of God the deceiver was unmasked. — {7LtMs, Lt 16a, 1892, par. 25}

Even the loyal angels did not fully discern his [Satan's] character. This was why God did not at once destroy Satan. Had He done so, the holy angels would not have perceived the justice and love of God. A doubt of God's goodness would have been as evil seed that would yield the bitter fruit of sin and woe. Therefore the author of evil was spared, fully to develop his character.— {COL 72}

It was necessary to give Satan time to develop his principles. He has had every opportunity to present his side of the question. He has been artful. As often as his position has been seen in its true light, he has changed to some other position. By making false charges, and by misstating the purposes and declared will of God, he has secured sympathizers. — {17LtMs, Ms 1, 1902, par. 4}