The answer from God’s word:
Everyone who has read the Bible knows that it is an account of the work God did during the Age of Law and the Age of Grace. The Old Testament of the Bible records the history of Israel and shows how Jehovah did His work from the creation of the world to the end of the Age of Law.… By recording the experiences and knowledge of those who served Jehovah and Jesus in the old and new ages, the Bible has given much inspiration, illumination, and many ways of practice to later generations. The reason that the Bible surpasses the writings of other great spiritual men is that their writings all draw their material from the Bible, and their experiences all stem from the Bible and are directed toward interpreting it. So even though people could draw sustenance from the books of any great spiritual man, they still worship the Bible, for they regard it as ever so lofty and profound. Some books of the Bible, like the letters of Peter and Paul, carry the word of life and can be a source of help and sustenance. But nevertheless they are out of date; they are writings of a past age. No matter how good they are, they are applicable only to one period of time, and will not last forever. For God’s work is always moving forward, it is not frozen in time at the age of Paul and Peter, will not remain forever fixed at the Age of Grace in which Jesus was crucified. So, these books are applicable only to the Age of Grace, not to the final Age of Kingdom; they were able to “He is merely working in the flesh, not intentionally asking for man to exalt the greatness and holiness of His flesh. He is simply showing man the wisdom of His work and all the authority He wields. Therefore, even though He has an outstanding humanity, He makes no announcements, and focuses only on the work that He should do. You should know why it is that God became flesh yet does not boast of or testify to His normal humanity, and instead simply carries out the work that He wishes to do. This is why you see only the being of divinity in God become flesh, simply because He never proclaims His being of humanity for man to emulate. … God conquers man through His work alone (that is, work unattainable to man). He does not impress man or make all mankind ‘worship’ Him, but simply instills in man a feeling of reverence for Him or makes man aware of His inscrutability. There is no need for God to impress man. All He needs is for you to revere Him once you have witnessed His disposition.”
from “The Mystery of the Incarnation (2)”
“My incarnation is for revealing all those who were born of Me but rise up to resist Me. If I were not incarnated, they could not be revealed (referring to those who act one way before Me and another behind My back). If I were still a Spirit, in man’s notions, all would come and worship Me, regarding Me as a God who has no form and image and who is too high to be approached. God incarnate of today is, just contrary to man’s notions (concerning My height and appearance), plain-looking and not tall. This shames Satan the most, and is the most powerful counterattack against man’s notions (Satan’s blasphemies). If My appearance were out of the ordinary, there would be a trouble. Everyone would come and worship Me, all would know Me by man’s notions, and they would not be able to bear the good testimony for Me. So, I took today’s image. It is not difficult to understand at all. Everyone should come out of man’s notions, and do not fall into Satan’s schemes.”
from “The Ninety-first Utterance”
“Though Christ on earth is able to work on behalf of God Himself, He does not come with the intention of showing all men His image in the flesh. He does not come for all men to see Him; He comes to allow man to be led by His hand, thereby entering into the new age. The function of Christ’s flesh is for the work of God Himself, that is, for the work of God in the flesh, and not to enable man to fully understand the substance of His flesh. No matter how He works, it does not exceed that which is attainable to the flesh. No matter how He works, He does so in the flesh with a normal humanity, and does not fully reveal to man the true countenance of God. Additionally, His work in the flesh is never as supernatural or inestimable as man conceives. … God becomes flesh only to complete the work of the flesh, not simply to allow all men to see Him. Rather, He lets His work affirm His identity, and allows what He reveals to attest to His substance. …
… Though His image is not pleasing to the senses, His discourse not possessed of an extraordinary air, and His work not as earth-shattering or heaven-shaking as man imagines, He is indeed Christ, who fulfills the will of the heavenly Father with a true heart, completely submits to the heavenly Father, and is obedient to the death. This is because His substance is the substance of Christ. This truth is hard for man to believe but does indeed exist.”
from “The Substance of Christ Is Obedience to the Will of the Heavenly Father”