Every contradiction between the teachings of Joseph Smith and a revelation from the Lord is a witness that Joseph was a true prophet. Do you understand why?
A revelation is when the Lord "Reveals New Information". If the revelation revealed something you already new, understood or believed, it wouldn't be a revelation. Why would the Lord tell us something we already knew and understood?
If Joseph was making up fake revelations then he would make the revelations support what he already knew and believed because its no fun to believe you're right about something, teach I to everyone and then get a revelation saying that you don't know what you're talking about. And if you wanted other people to believe what you believe, you would make the Lord agree with you in your Revelations that you made up so you could keep believing what you want.
I have had the experience of teaching something then getting a revelation telling me I was wrong and having to recant as a result. I have also had revelations that I couldn't understand or accept for 5-6 years. During that time, I taught what I believed and not what was in the revelation. The contradiction between my understanding/beliefs and the revelation from the Lod was proof that the revelation was not the creation of my own mind, thoughts and desires.
Here is an example of Joseph Smith teaching his personal views which are contrary to the revelations from the Lord. Since most people aren't ready to understand and accept the revelation or new information from the Lord without significant effort to explain it, I'll just give some references where the Lord says Joseph doesn't know, understand and comprehend the subject matter.
Here is Joseph teaching his own views regarding God the Father from D&C 130.
Here the Lord is revealing that Joseph doesn't know or understand what he worships (the Father) and the Lord isaid the previous verses 1-19 attempting to reveal to Joseph this new information.D&C 130
22 The Father has a body of flesh and bones as tangible as man’s; the Son also; but the Holy Ghost has not a body of flesh and bones, but is a personage of Spirit. Were it not so, the Holy Ghost could not dwell in us.
Here is another reference where the Lord tells Joseph that he doesn't comprehend God. He promises Joseph that a day will come when he does comprehend God and when that day comes Joseph is told that he will realize that he has seen God, he will understand why his name is "I AM", and he will realize the God is the in Joseph and also that Joseph is in God.D&C 93
19 I give unto you these sayings that you may understand and know how to worship, and know what you worship, that you may come unto the Father in my name, and in due time receive of his fulness.
20 For if you keep my commandments you shall receive of his fulness, and be glorified in me as I am in the Father; therefore, I say unto you, you shall receive grace for grace.
BTW. all these promises apply not only to Joseph but to everyone reading this. If you do not think you have seen God, then you do not comprehend God. "Nevertheless, the day shall come when you shall comprehend even God, being quickened in him and by him. Then shall ye know that ye have seen me, that I am, and that I am the true light that is in you, and that you are in me."D&C 88
49 The light shineth in darkness, and the darkness comprehendeth it not; nevertheless, the day shall come when you shall comprehend even God, being quickened in him and by him.
50 Then shall ye know that ye have seen me, that I am, and that I am the true light that is in you, and that you are in me; otherwise ye could not abound.
Because Joseph received revelations that he didn't comprehend or understand and which he contradicted in his own teachings, we know he wasn't making up the revelations according to his own beliefs and views to make it appear that the Lord was bolstering his position. Instead, the Lord disagreed with Joseph which diminished his position.
So, we learn to study and trust the revelations over the person who received them. When there is a contradiction between the person and the revelation we trust the revelation, assuming that it is a true prophet. It it is not a true prophet, then we trust neither the personnor the revelations they received.
In this case, the Lord repeatedly told Joseph that Joseph didn't comprehend, know or understand God the Father, or What he worships. So, whatever Joseph taught on this subject prior to receiving, understanding and accepting the revelations is wrong. As far as I can tell Joseph never changed his view of God since the first vision. So, his first vision view of God was wrong. Probably because it was a symbolic vision and not a litteral visitation and Joseph interpreted the vision as litteral and not symbolic.
This is true of any revelation Joseph had. All revelations are new information and should result in corrections or changes to previously believed information. Prophet's are people and don't always understand the revelations. So, it is expected that they will teach contrary to their own revelations, and when they do, it is proof that the revelation was not their own concoction but a new idea from a more brilliant mind.
Every contradiction between the teachings of Joseph Smith and a revelation from the Lord is a witness that Joseph was a true prophet. Do you understand why now?
~Seeker