The answer from God’s word:
“Though Jesus did much work among man, He only completed the redemption of all mankind and became man’s sin offering, and did not rid man of all his corrupt disposition. Fully saving man from the influence of Satan not only required Jesus to take on the sins of man as the sin offering, but also required God to do greater work to completely rid man of his disposition, which has been corrupted by Satan. And so, after man was forgiven his sins, God has returned to flesh to lead man into the new age, and begun the work of chastisement and judgment, and this work has brought man into a higher realm. All those who submit under His dominion shall enjoy higher truth and receive greater blessings. They shall truly live in the light, and shall gain the truth, the way, and the life.
… when God becomes flesh this time, His work is to express His disposition, primarily through chastisement and judgment. Using this as the foundation, He brings more truth to man, shows more ways of practice, and so achieves His objective of conquering man and saving man from his corrupt disposition. This is what lies behind the work of God in the Age of Kingdom.”
from Preface to The Word Appears in the Flesh
“A sinner such as you, who has just been redeemed, and has not been changed, or been perfected by God, can you be after God’s heart? For you, you who are still of your old self, it is true that you were saved by Jesus, and that you are not counted as sinners because of the salvation of God, but this does not prove that you are not sinful, and are not impure. How can you be saintly if you have not been changed? Within, you are beset by impurity, selfish and mean, yet you still wish to descend with Jesus—you should be so lucky! You have missed a step in your belief in God: You have merely been redeemed, but have not been changed. For you to be after God’s heart, God must personally do the work of changing and cleansing you; if you are only redeemed, you will be incapable of attaining sanctity. …”
from “Concerning Appellations and Identity” in The Word Appears in the Flesh
“Man received much grace, such as the peace and happiness of the flesh, the blessing of the entire family upon the faith of one, and the healing of sicknesses, and so on. The rest were the good deeds of man and their godly appearance; if man could live based on such, he was considered a good believer. Only such believers could enter heaven after death, which means that they were saved. But, in their lifetime, they did not understand at all the way of life. They merely committed sins, then made confession in a constant cycle without any path toward a changed disposition; such was the condition of man in the Age of Grace. Has man received complete salvation? No! Therefore, after that stage was complete, there is still the work of judgment and chastisement. This stage makes man pure through the word so as to give man a path to follow. This stage would not be fruitful or meaningful if it continued with the casting out of demons, for the sinful nature of man would not be cast away and man would only stop upon the forgiveness of sins. Through the sin offering, man has been forgiven his sins, for the work of the crucifixion has already come to an end and God has prevailed over Satan. But the corrupt disposition of man still remains within them and man can still sin and resist God; God has not gained mankind. That is why in this stage of work God uses the word to reveal the corrupt disposition of man and asks man to practice in accordance with the right path. This stage is more meaningful than the previous one and more fruitful as well, for now it is the word that directly supplies life for man and enables the disposition of man to be completely renewed; it is a stage of work more thorough. Therefore, the incarnation in the last days has completed the significance of God’s incarnation and completely finished God’s management plan for the salvation of man.
… In the work of the last days, the word is mightier than the manifestation of signs and wonders, and the authority of the word surpasses that of signs and wonders. The word reveals all the corrupt dispositions in the heart of man. You are unable to recognize them on your own. When they are revealed to you through the word, you will naturally come to the realization; you will not be able to deny them, and you will be utterly convinced. Is this not the authority of the word? This is the result achieved by the present work of the word. Therefore, man cannot be fully saved from his sins by the healing of sickness and casting out of demons and cannot be fully made complete by the manifestation of signs and wonders. The authority to heal and cast out demons only gives man grace, but the flesh of man still belongs to Satan and the corrupt satanic disposition still remains within man. In other words, that which has not been made clean still belongs to sin and filth. Only after man has been made clean through words can he be gained by God and become sanctified. If no more is done than casting out the demons within man and redeeming him, that is only seizing him from the hands of Satan and returning him to God. However, he has not been made clean or changed by God, and he remains corrupt. Within man still exists filth, opposition and rebelliousness; man has only returned to God through redemption, but man has no knowledge of Him and still resists and betrays God. Before man was redeemed, many of Satan’s poisons were already planted within him. After thousands of years of Satan’s corruption, man already has within him a nature that resists God. Therefore, when man has been redeemed, it is nothing more than redemption, where man is bought at a high price, but the poisonous nature within has not been eliminated. Man that is so defiled must undergo a change before being worthy to serve God. Through this work of judgment and chastisement, man will fully come to know the filthy and corrupt substance within him, and he will be able to completely change and become clean. Only in this way can man be worthy to return before the throne of God. All the work done this day is so that man can be made clean and be changed; through judgment and chastisement by the word, as well as refinement, man can cast away his corruption and be made pure. Rather than deeming this stage of work to be that of salvation, it would be more apt to say it is the work of purification. In truth, this stage is that of conquest as well as the second stage of salvation. Man is gained by God through judgment and chastisement by the word; through the use of the word to refine, judge and disclose, all of the impurities, notions, motives, and individual hopes within man’s heart are completely revealed. Though man has been redeemed and forgiven of his sins, it is only considered as God not remembering the transgressions of man and not treating man in accordance with man’s transgressions. However, when man lives in the flesh and he has not been set free from sin, he can only continue to sin, endlessly revealing the corrupt satanic disposition. This is the life that man leads, an endless cycle of sin and forgiveness. The majority of men sin in the day only to confess in the evening. As such, even if the sin offering is forever effective for man, it would not be able to save man from sin. Only half the work of salvation has been completed, for man still has corrupt disposition. … So, what you have experienced in the present are results achieved through the word, even greater than that achieved through Jesus’ working of signs and wonders. The glory of God and authority of God Himself that you see are not merely seen through the crucifixion, healing of sickness and casting out of demons, but more so through His judgment by the word. This shows you that not only the working of signs, healing of sickness and casting out of demons are the authority and power of God, but judgment by the word is better able to represent the authority of God and to reveal His almightiness.”
from “The Mystery of the Incarnation (4)” in The Word Appears in the Flesh