The answer from God’s word:
“Although some people believe in Almighty God, they have no knowledge about God’s almightiness at all. They have always been confused about this: Since God is almighty and since He has authority and can rule over all things, why did He create Satan, and allow it to corrupt mankind for six thousand years and create pandemonium in the world? Why doesn’t He destroy it? Won’t mankind be well if it is destroyed? Can you explain this question now? This has to do with the vision. … What kind of mankind is the group of people born in the last days? They are the ones who have been corrupted by Satan for thousands of years and who have been most deeply corrupted and have no human likeness. In the end, after they have been conquered through the judgment, chastisement, and disclosure of God’s words, they gain the truth from these words of God, are sincerely convinced of God, know God, and can absolutely obey God and satisfy God’s heart’s desire. God’s management plan is ultimately to gain such a group of people. Who do you say can satisfy God’s heart’s desire, the uncorrupted ones or the ones saved in the end? The mankind gained through the entire management plan is a group of people who are able to understand God’s will, who have gained the truth from God, and who possess the very life and likeness of man required by God. The mankind created in the beginning merely had man’s likeness and man’s life, but they did not possess the very likeness God requires and hopes man to have. The group of people gained in the end are the ones who will finally remain, and are also a group of people whom God wants and likes and whom God is satisfied with. In the several-thousand-year management plan, these people have gained more, and it is watered and supplied to them through God’s warring against Satan. Such a group of people are even better than the mankind God created in the beginning. They have been corrupted, but this is inevitable and is something within the management plan, which fully shows God’s almightiness and wisdom and that what God has arranged and planned and what God has accomplished are all the best.”
from “Only by Knowing God’s Almightiness Can One Have the True Faith” in Records of Christ’s Talks With Leaders and Workers of the Church
“My entire management plan, which spans six thousand years, consists of three phases, or three ages: first, the Age of Law; second, the Age of Grace (which is also the Age of Redemption); and finally, the Age of Kingdom. My work in these three ages differs according to the nature of each age, but at each stage it accords with man’s needs—or rather, it varies according to the tricks that Satan employs in My war against it. The purpose of My work is to defeat Satan, to make manifest My wisdom and omnipotence, to expose all Satan’s tricks and thereby to save all of humanity, which lives under its domain. It is to show My wisdom and omnipotence while at the same time revealing the hideousness of Satan. Moreover, it is to teach My creations to discriminate between good and evil, to recognize that I am the Ruler of all things, to see clearly that Satan is humanity’s foe, the lowest of the low, the evil one, and to make the difference between good and evil, truth and falsehood, holiness and filth, greatness and baseness, as clear as day. This way, ignorant humanity may bear witness to Me that it is not I who corrupt humanity, and only I—the Creator—can save humanity, can bestow upon them things for enjoyment; and they may come to know that I am the Ruler of all things and Satan is merely one of My creations, which later turned against Me.”
from “The Truth Concerning the Work in the Age of Redemption” in The Word Appears in the Flesh
“Now you should notice that God does not eliminate Satan right away, so that man is able to see how Satan has corrupted people, and how God has saved people. Only after man is able to see the extent of Satan’s corruption of man, how Satan’s list of crimes reaches the heavens does God ultimately eliminate Satan, so that people can see God’s righteousness, and that therein is the righteousness of God and His disposition. Everything that God does is righteous. Though you are unable to discover it, you should not make judgment as you please. If it appears to you as irrational, or if you have a conception about it, and then say God is not righteous, this is the most unwise.”
from “How to Understand the Righteous Disposition of God” in Records of Christ’s Talks With Leaders and Workers of the Church
