I would like to add my thoughts, maybe they will help someone, maybe someone can help me.
My opinion is that one of the “most important, and least discussed Bible verse” is 2Thessalonians 2:10, “Many are perishing because they have not accepted the love of the truth.” What does it mean to “love the truth”, except to desire it, seek it, with our whole heart, mind, soul, and strength? How sad it is when someone, especially a ‘believer’, says explicitly, “I do not care what God wants me to know or believe, I am to busy, I do not have time.” How sad it is when we implicitly show this same sad attitude by our actions. God wants us to love the truth and to honestly and humbly try and find out all we can about Him, by His grace, because in His infinite Goodness He wants to share Himself and knowledge of Himself with us; always knowing that there will be times (many?) where God will say it is better for us, for now, to not be given the whole answer we are seeking. When this appears to be the case, we should ask God, "Do you want me to keep butting my head against this wall, perseverance being a virtue, or do you want me to practice resignation and patience and wait for you to tell me when to try again?
On the issue of Three persons in One God; I try to remember to add the important word “divine” to the middle. When I consciously add this, I am less likely to attribute human qualities to God. God is infinite spirit, He must be the infinite perfection of every virtue. He must be, and is, infinite sharing. He must be indivisible, perfectly simple because it is not an infinite God if you have only part of Him. Starting from: Jesus is the only begotten Son of the Father, what must follow?
1. Because He is begotten, Jesus must have the same DIVINE nature. Therefore, He is infinite in all His attributes; indivisible, perfectly simple, All-Knowing, All-Loving, and All-Powerful, with one, single, infinite, eternally in the present tense, outside of time, and throughout time, thought.
2. God the Father and God the Son are eternally giving and receiving, in the eternally present tense, everything they posess, giving themselves completely and perfectly down to the “smallest” detail, sharing completely but not giving up their individual identities as only infinitely powerful, perfectly simple, spirits can, and this total giving and receiving is their infinite love for the other.
3. This Infinite gift of each to the other must be an infinite, divine person, The Holy Spirit, because (there is an infinite gift going back and forth and in this total giving of one infinite being to another infinite being, nothing else could describe it except another Divine Person), and because Jesus said that after He ascended to the Father, He would send another paraclete who would remind them of all things. The use of the word “who” proves that the Holy Spirit must be a person and divine because Jesus commanded the Apostles to baptise everyone in the Name (singular) of the Father, and of the Son, and of the Holy Spirit. Therefore the Three are One, because the Name name’s them, and that name must be “Jesus”. CCC 2666