Hi Lax16- Thank you for your courtesy.
You bet!
Yes, I believe in the law of eternal progression as taught by Joseph Smith. I could not answer the original question, because if I said yes, it would imply that I did not believe God is eternal. Since this is recorded in the Doctrine & Covenants, if I had to pick one or the other this is the one I would choose. I believe that God is eternal with no beginning and no end. I also believe that man is eternal without beginning or end.
If God is eternal and yet He had parents, how could He have no beginning and no end?
“Man was also in the beginning with God. Intelligence, or the light of truth, was not created or made, neither indeed can be.” (D&C 93:29)
Does this come from any other source other than the revelations of Joseph Smith?
Now, can you answer a question for me?
Do you believe that 3 persons can be one God if they are of the same substance?
As stated in the Athanasian Creed: the Father is God, the Son is God, and the Holy Spirit is God and yet there not three Gods but one God.
They are distinct but all together in one God.
The Catechism of the Catholic Church explains this difficult concept very well:
The dogma of the Holy Trinity
253 The Trinity is One. We do not confess three Gods, but one God in three persons, the “consubstantial Trinity”.83 **The divine persons do not share the one divinity among themselves but each of them is God whole and entire: **"The Father is that which the Son is, the Son that which the Father is, the Father and the Son that which the Holy Spirit is, i.e. by nature one God."84 In the words of the Fourth Lateran Council (1215), "Each of the persons is that supreme reality, viz., the divine substance, essence or nature."85
254 The divine persons are really distinct from one another. "God is one but not solitary."86 “Father”, “Son”, “Holy Spirit” are not simply names designating modalities of the divine being, for they are really distinct from one another: "He is not the Father who is the Son, nor is the Son he who is the Father, nor is the Holy Spirit he who is the Father or the Son."87 They are distinct from one another in their relations of origin: "It is the Father who generates, the Son who is begotten, and the Holy Spirit who proceeds."88 The divine Unity is Triune.
255 The divine persons are relative to one another. Because it does not divide the divine unity, the real distinction of the persons from one another resides solely in the relationships which relate them to one another: "In the relational names of the persons the Father is related to the Son, the Son to the Father, and the Holy Spirit to both. While they are called three persons in view of their relations, we believe in one nature or substance."89 Indeed "everything (in them) is one where there is no opposition of relationship."90 "Because of that unity the Father is wholly in the Son and wholly in the Holy Spirit; the Son is wholly in the Father and wholly in the Holy Spirit; the Holy Spirit is wholly in the Father and wholly in the Son."91
It seems that the BoM has a more traditional view of the Trinity than current LDS teaching- why is that?
For example, Alma 11:44, Mosiah 15:5-7, and 2 Nephi 31:21.
Also, in The Testimony of Three Witnesses at the beginning of the BoM, it says: “And the honor be to the Father, and to the Son, and to the Holy Ghost, which is one God. Amen.”