The Answer from God’s Word:
First, He is able to open up a new age; second, He is able to supply the life of man and show man the way to follow. This is sufficient to establish that He is God Himself. At the very least, the work He does can fully represent the Spirit of God, and from such work it can be seen that the Spirit of God is within Him. As the work done by the incarnate God was mainly to usher in a new age, lead new work, and open up new circumstances, these few conditions alone are sufficient to establish that He is God Himself.
from “The Difference Between the Ministry of the Incarnate God and the Duty of Man” in The Word Appears in the Flesh
To study such a thing is not difficult, but requires each of us to know this truth: He who is God’s incarnation shall hold the substance of God, and He who is God’s incarnation shall hold the expression of God. Since God becomes flesh, He shall bring forth the work He must do, and since God becomes flesh, He shall express what He is, and shall be able to bring the truth to man, bestow life upon man, and show man the way. Flesh that does not contain the substance of God is surely not the incarnate God; of this there is no doubt. To investigate whether it is God’s incarnate flesh, man must determine this from the disposition He expresses and the words He speaks. Which is to say, whether or not it is God’s incarnate flesh, and whether or not it is the true way, must be judged from His substance. And so, in determining[a] whether it is the flesh of God incarnate, the key is to pay attention to His substance (His work, His words, His disposition, and many more), rather than external appearance. If man sees only His external appearance, and overlooks His substance, then that shows the ignorance and naivety of man. External appearance does not determine substance; what’s more, the work of God has never conformed with the conceptions of man. Did not the outward appearance of Jesus conflict with the conceptions of man? Were not His appearance and dress unable to provide any clues as to His true identity? Was not the reason why the earliest Pharisees opposed Jesus because they merely looked at His external appearance, and did not take to heart the words that He spoke? It is My hope that the brothers and sisters who seek the appearance of God will not repeat the tragedy of history. You must not become the Pharisees of modern times and nail God to the cross again. You should carefully consider how to welcome the return of God, and should have a clear mind of how to be someone who submits to the truth. This is the responsibility of everyone who is waiting for Jesus to return with the clouds.
from Preface to The Word Appears in the Flesh