Jesus taught "And this is life eternal, that they might know thee the only true God, and Jesus Christ, whom thou hast sent" John 17
Your creed written by men, by the arm of flesh tells me God is incomprehensible when the Bible says it's the darkness which can not comprehend.
"Your creed was written by men" -- and Joseph Smith was
what, then? A man, correct? It detracts from whatever point you are trying to make by following this with a lengthy exposition from your preferred man, Joseph Smith.
And so as you done with your own church's chief theologian, here is an actual Church father's exposition on the piece of scripture that you have mutilated in order to continue to deny God. From our father among the saints St. Cyril of Alexandria:
CHAPTER V. That the Son will not be excluded from being true God, even though He named God the Father the only true God.
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And this is life eternal, that they should know Thee the only true God, and Him Whom Thou didst send, even Jesus Christ.
He defines faith as the mother of eternal life, and says that the power of the true knowledge of God will be such as to cause us to remain for ever in a state of incorruption, and blessedness, and sanctification. And we say that that is true knowledge of God, which cannot incur the reproach of turning aside to aught else, or running after things unseemly. For some have
worshipped the creature rather than the Creator, and have dared to say to a block of wood:
Thou art my Father; and to a stone, Thou hast begotten me. For to such abysmal ignorance did miserable men relapse, that they even gave, in all its fulness, the great Name of God, to senseless blocks of wood; and invested them with the ineffable glory of that Nature, which is over all. He calls God the Father, then, the only true God, by contrast to spurious gods, and with the intention to distinguish the true God, from those who are so named in error; for this is the object of His words. Very appropriately, then, He first speaks of God as being One and One only, and then makes mention of His own glory in the words:
And Jesus Christ Whom Thou hast sent. For a man can in nowise attain to complete knowledge of the Father, unless side by side, and in most intimate connexion with it, he lay hold on the knowledge of His Offspring; that is, the Son. For, if a man know what the Father is, he cannot but know also the Son. When, then, He said that the Father was the true God, He did not exclude Himself. For being in Him, and of Him, by Nature, He will be also Himself the true God and the only God, as He is the only God: for beside Him, there is none other god who is the only true God.
For the gods of the heathen are devils. For the creation is enslaved, and I know not how any worship them, or sink into such a slough of unreasoning and sensuous folly. With the many gods, then, in this world, who are erroneously so conceived, and have won this spurious title, the only true God is brought into contrast; and the Son also, Who is by Nature in Him, and of Him, at once in diversity and in identity of Nature, according to a natural Unity. I say in diversity of Nature, because He has in fact an individual Existence; for the Son
is the Son, and not the Father. In identity of Nature also, because the Son, Who came forth from Him, is inseparably joined by Nature, with the existence of His Father. For the Father is one with the Son, even though He is the Father; and is so spoken of, because He did in fact beget Him.
-- Cyril of Alexandria, Commentary on John, LFC 43, 48 (1874/1885), Book 11, Vol.2 [Translator: T. Randell] (Italics at source)
Joseph Smith God's prophet said;
"This is life eternal"--to know God and Jesus Christ, whom he has sent. If any man, not knowing what kind of a being God is, inquires to know if the declaration of the apostle is true--and searches diligently his own heart--he will admit that he has not eternal life; for there can be no eternal life on any other principle. My first object is to find out the character of the only wise and true God,...I want you all to know God, to be familiar with him....First, God himself, who sits enthroned in yonder heaven, is a man like one of you. That is the great secret. If the veil were rent today and you were to see the great God who holds this world in its orbit and upholds all things by his power, you would see him in the image and very form of a man; for Adam was created in the very fashion and image of God. He received instruction from and walked, talked, and conversed with him as one man talks and communes with another."
Let's see one tells me I can not understand God and the other explains God very plainly. Which should I believe?
You should believe St. Cyril of Alexandria. How is this even a question? Is the 'plainness' of explanation in conveying theology what determines what is true and what is not? No.