The answer from God’s word:
“Some believe that God may sometime come to earth and appear to man, whereupon He shall personally judge the whole of mankind, testing them one by one without anyone being omitted. Those who think in this way do not know this stage of work of incarnation. God does not judge man one by one, and does not test man one by one; to do thus would not be the work of judgment. Is not the corruption of all mankind the same? Is not the substance of man all the same? What is judged is mankind’s corrupt substance, man’s substance corrupted by Satan, and all the sins of man. God does not judge the trifling and insignificant faults of man. The work of judgment is representative, and is not carried out especially for a certain person. Rather, it is work in which a group of people are judged in order to represent the judgment of all of mankind. By personally carrying out His work on a group of people, God in the flesh uses His work to represent the work of the whole of mankind, after which it is gradually spread. The work of judgment is also thus. God does not judge a certain kind of person or a certain group of people, but judges the unrighteousness of the whole of mankind—man’s opposition to God, for example, or man’s irreverence against Him, or disturbance of the work of God, and so on. What is judged is mankind’s substance of opposition to God, and this work is the work of conquest of the last days. The work and word of the incarnate God witnessed by man are the work of judgment before the great white throne during the last days, which was conceived by man during times past. The work that is currently being done by the incarnate God is exactly the judgment before the great white throne. The incarnate God of today is the God who judges the whole of mankind during the last days. This flesh and His work, word, and entire disposition are the entirety of Him. Although the scope of His work is limited, and does not directly involve the entire universe, the substance of the work of judgment is the direct judgment of all mankind; it is not work that is undertaken only for China, or for a small number of people. During the work of God in the flesh, although the scope of this work does not involve the entire universe, it represents the work of the entire universe, and after He concludes the work within the work scope of His flesh, He will immediately expand this work to the entire universe, in the same way that the gospel of Jesus spread throughout the universe following His resurrection and ascension. Regardless of whether it is the work of the Spirit or the work of the flesh, it is work that is carried out within a limited scope, but which represents the work of the entire universe. During the last days, God appears to do His work using His incarnate identity, and God in the flesh is the God who judges man before the great white throne. Regardless of whether He is the Spirit or the flesh, He who does the work of judgment is the God who judges mankind during the last days. This is defined based on His work, and is not defined according to His external appearance or several other factors. Although man has conceptions of these words, no one can deny the fact of the incarnate God’s judgment and conquest of all mankind. Regardless of how it is evaluated, facts are, after all, facts. No one can say that ‘The work is done by God, but the flesh is not God.’ This is nonsense, for this work can be done by no one except God in the flesh. … Because the one who is judged is man, man who is of the flesh and has been corrupted, and it is not the spirit of Satan that is judged directly, the work of judgment is not carried out in the spiritual world, but among man. No one is more suitable, and qualified, than God in the flesh for the work of judging the corruption of man’s flesh. If judgment were carried out directly by the Spirit of God, then it would not be all-embracing. Furthermore, such work would be difficult for man to accept, for the Spirit is unable to come face-to-face with man, and because of this, the effects would not be immediate, much less would man be able to behold the unoffendable disposition of God more clearly. Satan can only be fully defeated if God in the flesh judges the corruption of mankind. Being the same as man possessed of normal humanity, God in the flesh can directly judge the unrighteousness of man; this is the mark of His innate holiness, and of His extraordinariness. Only God is qualified to, and in the position to judge man, for He is possessed of the truth, and righteousness, and so He is able to judge man. Those who are without the truth and righteousness are not fit to judge others. If this work were done by the Spirit of God, then it would not be victory over Satan. The Spirit is inherently more exalted than mortal beings, and the Spirit of God is inherently holy, and triumphant over the flesh. If the Spirit did this work directly, He would not be able to judge all of man’s disobedience, and could not reveal all of man’s unrighteousness. For the work of judgment is also carried out through man’s conceptions of God, and man has never had any conceptions of the Spirit, and so the Spirit is incapable of better revealing the unrighteousness of man, much less of completely disclosing such unrighteousness. The incarnate God is the enemy of all those who do not know Him. Through judging man’s conceptions and opposition to Him, He discloses all the disobedience of mankind. The effects of His work in the flesh are more apparent than those of the work of the Spirit. And so, the judgment of all mankind is not carried out directly by the Spirit, but is the work of the incarnate God.”
from “Corrupt Mankind Is More in Need of the Salvation of God Become Flesh” in The Word Appears in the Flesh