Vindication of God's character is extremely important. Satan has hurled deceptions and falsehoods about God's character for millennia. Many people reject God because they believe lies about His character. God is setting all of this straight, and one day soon, everyone in the universe will be fully and clearly convinced that God's character is good and that Satan's is evil. Once God's character is fully vindicated, God's eternal kingdom will be fully established.

…when the great controversy shall be ended. Then, the plan of redemption having been completed, the character of God is revealed to all created intelligences. The precepts of His law are seen to be perfect and immutable. Then sin has made manifest its nature, Satan his character. Then the extermination of sin will vindicate God's love and establish His honor before a universe of beings who delight to do His will, and in whose heart is His law. (DA 764.3).

And this is eternal life, that they may know You, the only true God, and Jesus Christ whom You have sent. John 17:3

The last rays of merciful light, the last message of mercy to be given to the world, is a revelation of His character of love. COL 415.5

But not so when the great controversy shall be ended. Then, the plan of redemption having been completed, the character of God is revealed to all created intelligences. The precepts of His law are seen to be perfect and immutable. Then sin has made manifest its nature, Satan his character. Then the extermination of sin will vindicate God’s love and establish His honor before a universe of beings who delight to do His will, and in whose heart is His law. DA 764.3

[Jesus] came into the world for the express purpose of vindicating his Father's law. (LP 30.3).

Christ came to earth to maintain and exalt the divine law, by himself suffering the penalty of sin, and to thereby evidence that God will in no wise clear the guilty…. his mission to earth was to vindicate the supreme law of God, not to annul it. (ST March 7, 1878, par. 16).

Christ volunteered to maintain and vindicate the holiness of the divine law. Con 20.2

And thus Christ would fully vindicate His Father’s law. Con 21.3

The only-begotten Son of God accepts all the liabilities that fall upon the transgressor of the law, vindicates its unchangeable and holy character. The death of Christ removes every argument that Satan could bring against the precepts of Jehovah. (ST February 5, 1894, par. 10).

But it is ever the purpose of Satan to make void the law of God and to pervert the true meaning of the plan of salvation. … The atonement of Calvary vindicated the law of God as holy, just, and true, not only before the fallen world but before heaven and before the worlds unfallen. Christ came to magnify the law and to make it honorable. (FW 118.2).

Christ died to save sinners, not in their sins, but from their sins. The warning given in Revelation shows us the terrible consequence of transgression. By lips that will not lie, God's law is declared to be holy, just, and good. Our duty to obey this law is to be the burden of the last message of mercy to the world. God's law is not a new thing. It is not holiness created, but holiness made known. It is a code of principles expressing mercy, goodness, and love. It presents to fallen humanity the character of God, and states plainly the whole duty of man. (RH April 27, 1911, par. 2).

The final judgment is a most solemn, awful event. … God will be honored and His government vindicated and glorified, and that in the presence of the inhabitants of the unfallen worlds. On the largest possible scale will the government of God be vindicated and exalted. (21MR 349.1).

The Lord Jesus Christ came to our world to vindicate the honor and glory of God. (11LtMs, Ms 71, 1896, par. 19).

The Lord will interpose to vindicate His own honor. COL 177.5

whom God set forth as a propitiation by His blood, through faith, to demonstrate His righteousness, because in His forbearance God had passed over the sins that were previously committed, Romans 3:25

vindicate the righteousness of His Father’s word CEv 64.2

Paul … saw in the Man of Calvary the vindicator of truth, the fulfiller of prophecy. (ST June 23, 1887, par. 7).

We are to keep before the mind the sin-pardoning Saviour. But we are to present Him in His true position-coming to die to magnify the law of God and make it honorable, and yet to justify the sinner who shall depend wholly upon the merits of the blood of a crucified and risen Saviour. This is not made plain. (1888 430.1).

And shall God not avenge His own elect who cry out day and night to Him, though He bears long with them? Luke 18:7

These words are to administer comfort to all those who are oppressed. God hears the cries of his children. Jesus gives them the assurance that God has not forsaken, that he will come forth to vindicate their cause. There is One who has suffered in their behalf, who has borne with them their sorrows and afflictions, and who will appear as their deliverer. (ST May 21, 1896, par. 5).