The answer from God’s word:
The sins of man were forgiven through God incarnate, but it does not mean that man has no sin within him. The sins of man could be forgiven through the sin offering, but man has been unable to resolve the issue of just how he can no longer sin and how his sinful nature can be cast away completely and be transformed. The sins of man were forgiven because of the work of God’s crucifixion, but man continued to live in the old, corrupt satanic disposition. As such, man must be completely saved from the corrupt satanic disposition so that the sinful nature of man is completely cast away and never again develops, thus allowing the disposition of man to be changed. This requires man to understand the path of growth in life, the way of life, and the way to change his disposition. It also needs man to act in accordance with this path so that the disposition of man can gradually be changed and he can live under the shining of the light, and that he can do all things in accord with the will of God, cast away the corrupt satanic disposition, and break free from Satan’s influence of darkness, thereby emerging fully from sin. Only then will man receive complete salvation. … 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 is more meaningful than the previous one and more fruitful as well, for now it is the word that directly supplies man’s life 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.
… 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.
from “The Mystery of the Incarnation (4)” in The Word Appears in the Flesh
In his life, if man wishes to be cleansed and achieve changes in his disposition, if he wishes to live out a life of meaning, and fulfill his duty as a creature, then he must accept God’s chastisement and judgment, and must not allow God’s discipline and God’s smiting to depart from him, so he can free himself from the manipulation and influence of Satan and live in the light of God. Know that God’s chastisement and judgment is the light, and the light of man’s salvation, and that there is no better blessing, grace or protection for man. Man lives under the influence of Satan, and exists in the flesh; if he is not cleansed and does not receive God’s protection, then man will become ever more depraved. If he wishes to love God, then he must be cleansed and saved. …
… If man is not cleansed, then he is of the filth; if he is not protected and cared for by God, then he is still a captive of Satan; if he is not judged and chastised, then he will have no means of escaping the oppression of the dark influence of Satan. The corrupt disposition that you show forth and the disobedient behavior that you live out are sufficient to prove that you are still living under the domain of Satan. If your mind and thoughts have not been cleansed, and your disposition has not been judged and chastised, then your entire being is still controlled by the domain of Satan, your mind is controlled by Satan, your thoughts are manipulated by Satan, and your entire being is controlled by the hands of Satan. …
… Today’s truth is given to those who yearn for and seek it. This salvation is granted to those who yearn to be saved by God, and is not only meant to be gained by you, but is also so that you can be gained by God. You gain God in order that God can gain you. Today I have spoken these words to you, and you have heard them, and you should practice according to these words. In the end, when you put these words into practice will be when I have gained you through these words; at the same time, you will have also gained these words, which is to say, you will have gained this supreme salvation. Once you have been made clean, you will be a real human being.