The reason why so many Christians are so firm about Trinitarianism, is because they believe that it is a divine truth from the Holy Spirit.
When people believe a doctrine is a divine truth from the Holy Spirit, then there is little you can say to convince them otherwise.
Like I always say, "Truth is made known by the reason of the facts."
Facts first, feelings last. When I prayed about it, it was revealed to me that I had deceived myself by my own feelings.
From now on its facts first.
So, you received "truth from God" by prayer that you were being deceived by your feelings, and you accept that as actually being true. Yet, if a trinitarian prays and receives "truth from God" that the Trinity is true, they are wrong because they are being deceived by their feelings?
Do you see the problem there? If it is truly "facts first," then you ought to disregard the "revelation" from your prayer. You are using feelings to discount the use of feelings.
The Gnostic Christians believed in Sunday Sabbath, authority of the Pope, and Trinitarianism,
Please provide evidence.
Here is the oldest recorded document of Matthew 28:19.
"The Demonstratio Evangelica" by Eusebius:
Eusebius of Caesarea. 265 ? AD.– 337 ? AD.
Eusebius was the Church historian and Bishop of Caesarea. On page 152 Eusebius quotes the early book of Matthew that he had in his library in Caesarea. Eusebius informs us of Yahshua's actual words to his disciples in the original text of Matthew 28:19.
Quote: "With one word and voice He said to His disciples: "Go, and make disciples of all nations in My Name, teaching them to observe all...
And again Eusebius for example, in Book III of his History, Chapter 5, Section 2, which is about the Jewish persecution of early Christians, we read:
"But the rest of the disciples, who had been incessantly plotted against with a view to their destruction, and had been driven out of the land of Judea, went to all nations to preach the good news, relying upon the power of Christ, who had said to them, "Go ye and make disciples of all the nations in my name."
And yet The Didache, a much earlier document (late first/early second century), states: "baptize into the name of the Father, and of the Son, and of the Holy Spirit, in living water" (Chapter 7)
Didache. The Teaching of the Twelve Apostles (translation Roberts-Donaldson).
Just because Eusebius doesn't mention the trinitarian baptismal formula doesn't mean 1. that it wasn't in Matt 28:19, and 2. that it wasn't already accepted by the early church.
There is no mention of the word trinity in the entire Bible.
An old argument which is irrelevant to the truth of the matter.
Polycarp, Clement, and Ignatius were the students of the original disciples. They lived at the turn of the century, before and after 100 AD. They did not mention a trinity or give a description of a trinity in all their writings.
It was not until the second century AD that the idea of a trinity began to take shape in the Gnostic Christian community.
And yet Polycarp mentions worshiping Christ. Ignatius, in his letter to the Ephesians, states "For Jesus Christ, our inseparable Life, is the mind of the Father," and:
7:2 There is one only physician, of flesh and of spirit, generate and ingenerate, God in man, true Life in death, Son of Mary and Son of God, first passible and then impassible, Jesus Christ our Lord.
Ignatius of Antioch to the Ephesians (Lightfoot translation)
In his letter to the Smyrneans: "I give glory to Jesus Christ, the God who has given you wisdom."
St. Ignatius of Antioch
It seems clear that prior to any real development in the doctrine of the Trinity, the idea that Jesus was God in the flesh was accepted within the early church. And, again, please provide evidence that it was the Gnostic "Christian" community that developed the doctrine.
That is what we find throughout the scriptures:
"Beside me there is no God." (Isa. 44:6.)
"I am God, and there is none else; there is no God beside me." (Isa. 45:5.)
"I am God, and there is none else." (Isa. 46:9.)
"One God and Father of all, who is above all." (Eph. 4:6.)
"Hear, o Israel, the Lord our God is one Lord." (Deut. 6.4.)
All affirmations of the monotheistic God of Judaism and Christianity, which Trinitarians uphold.
"There is but one God, the Father, whom made all things, and us by Himself , and one lord Jesus Christ, by whom we are in. (1 Cor. 8:6.)
What translation is this?
1Co 8:6 yet for us there is one God, the Father, from whom are all things and for whom we exist, and one Lord, Jesus Christ, through whom are all things and through whom we exist. (ESV)
Just as "from whom all things" implies that the Father is the Creator and not a creature, so "through whom are all things" implies that Christ was involved in the creative act and is not a creature.
"This is life eternal, that they might know you, the only true God, and Jesus Christ, whom He has sent." (John 17:3.)
Notice that eternal life is not only connected with God but with Christ.
There is also a document about a Kabbalist who suggested the Godhead is triune.
That there may be pagan or other beliefs which include a triune God in no way means that the Trinity is false.
Perhaps that is why Yahshua quoted this verse:
Mark 12:29.
"The most important one," answered Jesus, "is this: 'Hear, O Israel, the Lord our God, the Lord is [one / only.]
This is a quite from Deut 6:4 which is a statement of monotheism, not of the inner workings or nature of God.