What appears to be happening here is that Catholics want us to believe the doctrine of the Trinity not because Scripture is chock full of references to the members of the Godhead, but rather because the Catholic church (allegedly) formally came up with the doctrine. So they want us to take it on the RCC authority, and not the authority of Scripture.
Matthew 12:15-18 15Jesus, aware of this, withdrew from there. And many followed him, and he healed them all 16and ordered them not to make him known. 17 This was to fulfill what was spoken by the prophet Isaiah: 18 "Behold, my servant whom I have chosen, my beloved with whom my soul is well pleased. I will put my Spirit upon him, and he will proclaim justice to the Gentiles.
Matthew 12:25-3225 Knowing their thoughts, he said to them, "Every kingdom divided against itself is laid waste, and no city or house divided against itself will stand. 26And if Satan casts out Satan, he is divided against himself. How then will his kingdom stand? 27And if I cast out demons by Beelzebul, by whom do your sons cast them out? Therefore they will be your judges. 28But if it is by the Spirit of God that I cast out demons, then the kingdom of God has come upon you. 29Or how can someone enter a strong man’s house and plunder his goods, unless he first binds the strong man? Then indeed he may plunder his house. 30 Whoever is not with me is against me, and whoever does not gather with me scatters. 31 Therefore I tell you, every sin and blasphemy will be forgiven people, but the blasphemy against the Spirit will not be forgiven. 32And whoever speaks a word against the Son of Man will be forgiven, but whoever speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come.
Luke 3:21-23 21Now when all the people were baptized, and when Jesus also had been baptized and was praying, the heavens were opened, 22and the Holy Spirit descended on him in bodily form, like a dove; and a voice came from heaven, "You are my beloved Son; with you I am well pleased."
John 15:26 "But when the Helper comes, whom I will send to you from the Father, the Spirit of truth, who proceeds from the Father, he will bear witness about me.
Acts 7:55 But he, full of the Holy Spirit, gazed into heaven and saw the glory of God, and Jesus standing at the right hand of God.
That’s exactly what they want. It’s the herd mentality. It’s more comfortable if everyone believes the same as they do. It gives them the feeling that they are not by themselves. They fear the “narrow road” as it leaves them vulnerable. Security in numbers and all that.
Just when you think you’ve read it all, that it cannot possibly be more presumptive or preposporus, here comes another doctrine down the pike.