What is the difference between the words of God conveyed by prophets in the Age of Law and the words of God expressed by God incarnate?
Relevant Words of God:
In the Age of Grace, Jesus also spoke much and did much work. How was He different from Isaiah? How was He different from Daniel? Was He a prophet? Why is it said that He is Christ? What are the differences between them? They were all men who spoke words, and their words appeared more or less the same to man. They all spoke and did work. The prophets of the Old Testament made prophecies, and similarly, so could Jesus. Why is this so? The distinction here is based on the nature of the work. In order to discern this matter, you cannot consider the nature of the flesh and you should not consider the depth or superficiality of one’s words. Always you must first consider his work and the effects his work achieves in man. The prophecies spoken by Isaiah at the time did not supply the life of man, and the messages received by those such as Daniel were merely prophecies and not the way of life. If not for the direct revelation of Jehovah, none could have done that work, for it is not possible for mortals. Jesus, too, spoke much, but such words were the way of life from which man could find a path to practice. That is to say, first, He could supply the life of man, for Jesus is life; second, He could reverse the deviations of man; third, His work could succeed that of Jehovah in order to carry on the age; fourth, He could grasp the needs of man within and understand what man lacks; fifth, He could usher in a new age and conclude the old. That is why He is called God and Christ; not only is He different from Isaiah but also from all other prophets. Take Isaiah as a comparison for the work of the prophets. First, he could not supply the life of man; second, he could not usher in a new age. He was working under the leadership of Jehovah and not to usher in a new age. Third, what he himself spoke of was beyond his comprehension. He was receiving revelations directly from the Spirit of God, and others would not understand, even having listened to them. These few things alone are sufficient to prove that his words were no more than prophecies, no more than an aspect of work done in Jehovah’s stead. He could not, however, completely represent Jehovah. He was Jehovah’s servant, an instrument in Jehovah’s work. He was only doing work within the Age of Law and within the scope of the work of Jehovah; he did not work beyond the Age of Law. On the contrary, the work of Jesus differed. He surpassed the scope of Jehovah’s work; He worked as the incarnate God and underwent crucifixion in order to redeem all mankind. That is to say, He carried out new work outside of the work done by Jehovah. This was the ushering in of a new age. Another condition is that He was able to speak of that which man could not achieve. His work was work within the management of God and involved the whole of mankind. He did not work in just a few men, nor was His work to lead a limited number of men. … 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. This thus differentiates Him from Isaiah, Daniel, and the other great prophets.
from “The Difference Between the Ministry of the Incarnate God and the Duty of Man” in The Word Appears in the Flesh