Why was it that Satan's existence was not cut short at the outset of his rebellion?--It was that the universe might be convinced of God's justice in His dealing with evil, that sin might receive eternal condemnation. . . .
As the nations of the saved look upon their Redeemer, and behold the eternal glory of the Father shining in His countenance; as they behold His throne, which is from everlasting to everlasting, and know that His kingdom is to have no end, they break forth in rapturous song. . . .
Mercy, tenderness, and parental love are seen to blend with holiness, justice, and power. While we behold the majesty of His throne, high and lifted up, we see His character in its gracious manifestations, and comprehend, as never before, the significance of that endearing title, "Our Father." . . .
The result of the Saviour's conflict with the powers of darkness is joy to the redeemed, redounding to the glory of God throughout eternity. From My Life Today - Page 368
Do not be afraid, little flock, for your Father has been pleased to give you the kingdom. Luke 12:32 (New International Version)