In the last days, the Lord sent prophets into the earth, not to say "follow me and be saved, for I am the light," but to say, seek the Lord as the Brother of Jared, be redeemed from the fall, brought back into the presence of the Lord and be prophets and seers yourselves."
It was this independence of heaven that caused Abraham to find his blessing, as did Isaac and Jacob each receive their own blessings. Moses tried to prepare Jacob's sons each, for themselves to know the Lord personally, but they wanted not only a spokesman, but for Moses to cover his head and hide the light which he reflected.
Joseph taught that one man cannot live upon the revelations given to another:
"If one man can live upon the revelations given to another, might not I with propriety ask, why the necessity, then, of the Lord speaking to Isaac as he did, as is recorded in the 26th chapter of Genesis? For the Lord there repeats, or rather promises again, to perform the oath which he had previously sworn unto Abraham. And why this repetition to Isaac? Why was not the first promise as sure for Isaac as it was for Abraham? Was not Isaac Abraham’s son? And could he not place implicit confidence in the word of his father as being a man of God?
"Perhaps you may say that he was a very peculiar man and different from men in these last days; consequently, the Lord favored him with blessings peculiar and different, as he was different from men in this age. I admit that he was a peculiar man and was not only peculiarly blessed, but greatly blessed. But all the peculiarity that I can discover in the man, or all the difference between him and men in this age, is that he was more holy and more perfect before God and came to him with a purer heart and more faith than men in this day."
"The same might be said on the subject of Jacob’s history. Why was it that the Lord spake to him concerning the same promise after he had made it once to Abraham and renewed it to Isaac? Why could not Jacob rest contented upon the word spoken to his fathers?...
"...the Lord hear [will] my prayers and listen to my cries as soon as he ever did to theirs if I come to him in the manner they did[.]" (Teachings of Presidents of the Church: Joseph Smith Prayer and Personal Revelation, original: Letter from Joseph Smith to his uncle Silas Smith, Sept. 26, 1833, Kirtland, Ohio; in Lucy Mack Smith, “The History of Lucy Smith, Mother of the Prophet,” 1845 manuscript, pp. 229–32, Church Archives.)