My respond to Donald who is Mormon

Part 1

D. //Homoousios has also been defined "of the same nature," and if we accept this definition, then we see a social trinity of three perfect beings - God, Jesus, and the Holy Ghost - working in perfect concert with each other, but each physically distinct. "Consubstantial" suggests the three are one being.//

M. Lets first look at this above it all, because it is an important misunderstanding and misconception that many non Trinitarians have.

To better understand the Catholic Teaching on the Holy Trinity we need to know the difference between Nature and Person.

Nature is what we are and person is who we are,

Nature is the source of what we are, person is what possesses the nature.

“NATURE answers the question—WHAT we are; PERSON answers the question—WHO we are. Every being has a nature; of every being we may properly ask, What is it? But not every being is a person: only rational beings are persons. We could not properly ask of a stone or a potato or an oyster, Who is it?” Theology and Sanity, part 6, page 92.

Mormonism and Oneness Pentecostals distort the image of who God is. Mormonism together with JWs separate the divinity of God and the Oneness Pentecostal unite God into one being which many Mormons think trinitarians do.

What my understanding of Mormon teachings on God is that they are three separate beings and thus it separates God into three gods who are only united in will, knowledge and purpose. If each is a distinct being, then what is it that one has and the other lacks. If the answer is nothing then they are the same being. If the answer is something then None are a supreme being which is by definition what God is.

What did the Council mean by using Homoousios? Well of course we know that they meant consubstantial since they rejected three different beings but used the word for "of the same nature" to represent that nothing was missing between the three persons.

The council thus was right in giving us the word homoousios. Yes it was a word that was used for the first time in history and It was so because there was not a word that was able to describe the relationship between Jesus Christ and God the Father. The Arians, were condemned at Nicaea, because they held that Christ was "divine" only in the sense that he was from God, and therefore like God, but not that he was literally "God from God, one in being with the Father."

Because of homoousios we have the Oneness of God, but not in the way it is taught in the Oneness Pentecostal nor Unitarian movements. We are different than God in our nature and we are not equal to Him in any way. Yes we are made in His image and likeness but this does not equate us to Him.

I believe because of this misunderstanding that Mormonism puts human aspects into who God is, thus you give Him a physical body which is not so. God is Spirit and in this we can not fully comprehend what it is to be spirit alone.

Scripture shows us this of what Spirit is, first it says this, “God is Spirit" (John 4:24), then it says, Behold my hands and my feet, that it is I myself. Handle me and see, FOR A SPIRIT does NOT have flesh and bones as you see I have (Luke 24:39). The d&c 22 states, “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.”

D&C is incorrect about the Spiritual part of life. Why is it that the Holy Spirit can be without flesh and bones and not the Father? As a matter of fact in the upper room where our Lord Jesus Christ appeared to the Apostles, Jesus Christ appeared in the room when everything was in lockdown.  In John's Gospel we see that the doors were shut and in Luke's Gospel we see that Jesus Christ has His resurrected body which was of flesh and bones.

EX nihilo is not taught in the Mormon church because it believes in a physical matter that preexisted and it has no scientific basis for evidence, which again is a human aspect and not a spiritual one, not everything has a physical matter. And God being God can do things we can not fully understand, such as ex-nihilo, which means create out of nothing.

God being who He is, that is Father, Son and Holy Spirit, is a mystery in which we can come to some understanding of the Truth but never into its fullest. Thus when it comes to the Spiritual aspects of God, we can not give Him human aspects.  

The Spiritual life can not be fully understood by our finite minds. Mormonism, to me, is wanting to say they know this of God, which I can not accept to be so because to know God in His fullness is not possible because He is a mystery. A mystery in which we can know, but never in its fullest.

Again it is in their Nature that He is One as Humanity's nature is one.

D. //I have a problem with homoousios, often translated as "consubstantial" or "of the same substance," because (1) I think Constantine's addition of the word in the original Creed of Nicaea actually made it more difficult to define the Saviour's relationship with His Father and (2) that fact alone has caused the Creed of Nicaea and the creeds that followed it to be interpreted too many ways.//

M. Firstly, let's get one thing correct, 1. Constantine had nothing to do with adding things to the Nicene Creed, the only two things he did was call for a council (and the Church took care of the rest). 2. And he signed the Edict of Milan, which made it legal to practice Christianity and ordered that the Christians’ confiscated property be returned to them.

Secondly, Homoousios, in Christianity is the key term of the Christological doctrine formulated at the first ecumenical council, at Nicaea in 325, to affirm that God the Son and God the Father are of the same substance. It did not give any leeway of interpreting it any other way. I believe this to be True because God is One and not three individuos beings as many (even some Catholics and Protestants) misunderstand and I believe that Joseph Smith had a misunderstanding of this Teaching as well.

I believe Homoousios made it better to understand the relationship between Father, Son and Holy Spirit.

What do we mean by One in being or consubstantial is that, His Divine Nature is One as Humanity's nature is one. No other human exists, as to no other Divine exists.

The being or the essence or nature or substance of God is His is-ness, the source of everything both visible and invisible.  I can agree with Mormons on God being One in His propess and knowledge, but if that is all that He is One in, then everything that Jesus Christ has done is meaningless because no mere creature can do what Jesus Christ has done and it makes Jesus into a creation of God and thus a separate being from what God is and so you have Two gods and not One, which is what Mormonism does to the Godhead. If God is only one in purpose and knowledge and not on being then it is here where it all goes wrong.

I also believe that homoousios better explains the relationship of Love between Father, Son and Holy Spirit.

The belief that God is only united in purpose is a heresy called Tritheism which popped out in the early 6th century after the heresy of Monophysitism and again in the 17th and then again in 19th century with Mormon belief.

Tritheism

The belief that cosmic divinity is composed of three powerful entities. As generally conceived, three gods are envisioned as having separate domains and spheres of influence that coalesce into an omnipotent whole. In this primary respect, tritheism differs from cosmic dualism, which often posits two divine powers working in theological or spiritual opposition.

Part 2

D. //Jesus made it clear that God is His Father, the Bible shows us they are two distinct personages. This rules out the extreme that homoousios is taken to, which is modalism, but it also tends to support homoiousios (of similar substance) a concept Arius took too far.//

M. Catholics do not deny that God is Jesus’ Father nor that the Son is a distinct Person from the Father and the Holy Spirit. As a matter of fact the Church has always taught the distinctions between the persons of the Trinity and not the being from one another. When we use the word distinction it does not mean separation from the Nature of God.

The Church states, The Father is not the Son and the Son is not the Father and neither are the Holy Spirit yet in what they are one in is God/Divine.

Modalism is the belief of the Oneness Pentecostal and Unitarian movement, the Jesus only movement. It is a heresy within the Catholic Church and Christianity in general today.

As a matter of fact before the Council of Nicaea it was already being held as a heresy and the Council is what defined this as we know it today. So the word homoousios does not have anything to do with the understanding of Modalism.

Tertullian,

If the number of the Trinity also offends you, as if it were not connected in the simple Unity, I ask you how it is possible for a Being who is merely and absolutely One and Singular, to speak in plural phrase, saying, Let us make man in our own image, and after our own likeness; Genesis 1:26 whereas He ought to have said, Let me make man in my own image, and after my own likeness, as being a unique and singular Being? (Against Praxeas Chapter 12, date between 190-220AD)

Pope Dionysius
"Next, then, I may properly turn to those who divide and cut apart and destroy the monarchy, the most sacred proclamation of the Church of God, making of it, as it were, three powers, distinct substances, and three godheads. I have heard that some of your catechists and teachers of the divine Word take the lead in this tenet. They are, so to speak, diametrically opposed to the opinion of Sabellius. He, in his blasphemy, says that the Son is the Father and vice versa" (Letters of Pope Dionysius to Bishop Dionysius of Alexandria 1:1 [A.D. 262]).

Modalism is also known as Sabellianism or Monarchianism. Praxeas and Sabellius, were early church figures that held this belief.  

As for homoiousios, yes it only states that Jesus Christ is similar to God but not God, which is why the Catholic uses the word homoousios because God is One in the same God/Divinity being/nature.

Monophysitism

The position called monophysitism asserted that in the person of Jesus Christ there was only one, divine nature rather than two natures, divine and human, as asserted at the Council of Chalcedon in 451A.D.