The Holy Trinity - Three Persons in One God. How in the world can anyone explain that? The answer is that we in this world cannot. It is a mystery beyond our comprehension. How can there be three separate persons- The Father, The Son, and The Holy Ghost - but yet still all be the same God? This is truly a question that we take on faith as Catholics, because our limited human brains simply cannot understand it. And while we cannot fathom this mystery, as Catholics we know and love this fact of three persons in one God. And by the way, the word "Trinity" does not appear in the Bible. Some of our protestant (one who protests against the Catholic Church) brothers and sisters use this strategy against Catholics concerning the word "purgatory", another word which doesn't appear in the Bible, but yet, the doctrine is. This doctrine of the Trinity was formulated over time, which fulfills the words of Jesus in John 16:12-13:
"I have yet many things to say to you, but you cannot bear them now. When the Spirit of truth comes, he will guide you into all the truth; for he will not speak on his own authority, but whatever he hears he will speak, and he will declare to you the things that are to come."
"If anyone denies that the Father is eternal, that the Son is eternal, and that the Holy Spirit is eternal: he is a heretic.If anyone says that the Son made flesh was not in heaven with the Father while He was on earth: he is a heretic.If anyone denies that the Holy Spirit has all power and knows all things, and is everywhere, just as the Father and the Son: he is a heretic."
"We confess and we believe that the holy and indescribable Trinity, Father, Son, and Holy Spirit is one only God in His nature, a single substance, a single nature, a single majesty and power. We acknowledge Trinity in the distinction of persons; we profess Unity because of the nature or substance. The three are one, as a nature, that is, not as person. Nevertheless, these three persons are not to be considered separable, since we believe that no one of them existed or at any time effected anything before the other, after the other, or without the other."
"Hear, O Israel: The LORD our God is one LORD; and you shall love the LORD your God with all your heart, and with all your soul, and with all your might."
These verses come right out and say that our God is one, as well as giving us a glimpse of the great Commandment that Jesus gave us in Matthew 22:37.
St. Patrick explained the doctrine of the Holy Trinity to his flock in Ireland by using the three leaves of the shamrock. Each leaf represented one of the three persons, but yet it was still only one shamrock. If we take a look at our self, each human is made up of a mind, a body, and a soul, and yet we are still only one person. A fire has flames, heat, and light, but yet it is still just one fire. When you hear a person's speech, you are hearing three things - his words, his thoughts, and his voice. When you strum one chord on a guitar, it is made up of 3 separate notes, all equal to each other. Everything in nature is in 3 dimensions - length, width, and height (coincidence?). And while these examples help to explain the concept of three in one, the Holy Trinity is so much more.
For instance, where Jesus is present, the Father and Holy Spirit are also present, because they are one. Where the Father is present, Jesus and the Holy Spirit are also present simultaneously. Where the Holy Spirit is present, the Father and Jesus are also present in one person (This constant three-in-one presence is called "circumincession".) This means that when we receive the Eucharist at Mass, which is truly the body, blood, soul, and divinity of Jesus Christ, we are also receiving the Father and the Holy Spirit, because they are one. When we are Confirmed and receive the Holy Spirit, we are also receiving the Father and Jesus as well. We know that Jesus Christ is physically present in every Tabernacle in every Catholic Church in the world, which means that the Father and the Holy Spirit are as well. This is very significant, because the Father and Jesus and the Holy Spirit also dwell in heaven at the same time, so the Tabernacle is a kind of gateway to heaven for the world, because of the Divine Presence that lives there every hour of every day of every month of every year.
And THAT is why it is so important to attend Mass and Adoration of the Blessed Sacrament as often as possible, because you are accessing heaven when you do! How many people walk into church and never genuflect before the Blessed Sacrament? How many people never go to confession to get absolution for their mortal sins before receiving the blessed Trinity on their tongue? How many people talk and visit before Mass like they are waiting for the curtain to go up in a theater, instead of praying and showing reverence for the Divine Presence? How many Masses are said with hardly any reverence and respect for the Holy Trinity dwelling in the Tabernacle? Way too many. If the Pope were to come to our church, we would all be beating down the door to get a good seat to see, hear, and maybe even shake his hand; but how many of us regularly attend Eucharistic Adoration so that we can adore Jesus Christ and the Father and the Holy Spirit in the Eucharist? A minuscule percentage of those of us who would go and see the Pope, that's for sure.
The Holy Trinity is first alluded to in the book of Genesis 1:26:
Then God said, "Let us make man in our image, after our likeness; and let them have dominion over the fish of the sea, and over the birds of the air, and over the cattle, and over all the earth, and over every creeping thing that creeps upon the earth."
Then Jesus came from Galilee to the Jordan to John, to be baptized by him. John would have prevented him, saying, "I need to be baptized by you, and do you come to me?" But Jesus answered him, "Let it be so now; for thus it is fitting for us to fulfill all righteousness." Then he consented. And when Jesus was baptized, he went up immediately from the water, and behold, the heavens were opened and he saw the Spirit of God descending like a dove, and alighting on him; and lo, a voice from heaven, saying, "This is my beloved Son, with whom I am well pleased."
even the Spirit of truth, whom the world cannot receive, because it neither sees him nor knows him; you know him, for he dwells with you, and will be in you.
"The first thing to note in this Gospel is the clear statement of faith in the Holy Trinity. The Holy Spirit is sent by the Father and the Son; and these three are of one substance, and inseparably equal. Unity is found in the essence, plurality in the persons. Whence, "The Lord clearly implies the unity of the divine essence, and the Trinity of persons, when he says in Matthew: Go, baptize all nations in the name of the Father and of the Son and of the Holy Spirit [Mt 28.19]. He says, ‘in the name’, not ‘in the names’, to show the unity of essence; but by adding three names, he indicates that there are three persons."
"In that Trinity there is the ultimate Origin of all things, the most perfect Beauty and the most blessed Delight. As St Augustine shows in his book, "On the true Religion," we understand the supreme Origin to be God the Father, from whom all things come, from whom come the Son and the Holy Spirit. We understand the most perfect Beauty to be the Son, the Truth of the Father, who resembles him in every way, and whom we worship with and in the Father himself. He is the form of all the things that are created from a single source, and which return to a single end. We understand the most blessed Delight and supreme Goodness to be the Holy Spirit, who is the gift of the Father and the Son. It is our duty to worship and hold on to this gift of God, as unchangeable as the Father and the Son. Thus by considering creation, we gain understanding of the Trinity in one substance, namely one God the Father from whom we exist, the Son through whom we exist, and the Holy Spirit in whom we exist. The Beginning to which we return, the Form which we imitate and the Grace by which we are reconciled." So that our mind may extend itself to contemplate the Creator, and believe without hesitation the Unity in Trinity and Trinity in Unity, let us see how the ‘vestiges’ of the Trinity appear in the mind itself.
St Augustine says in his book "On the Trinity," "Though human mind is not of the same nature as God, yet the image of him, than whom nothing is better, is to be sought and found in that part of our nature than which nothing is better: namely, the mind. See how the mind remembers itself, understands itself and loves itself. When we see this, we see a trinity; not God, but the image of God. There is a kind of trinity apparent in memory, understanding and love or will. These three are not three ‘lives’, but a single life. They are not three minds but a single mind, not three essences but a single essence. We attribute memory to a subject, and similarly understanding and will (or love) belong to a subject; but life, mind and essence are themselves that subject. These three are one: a single life, a single mind, a single essence."
"Although these three are distinct among themselves, we say they are one, because they exist substantially in the soul. The mind itself is, as it were, a parent; and its knowledge is, as it were, its offspring. When the mind knows itself, it begets an idea of itself, and it is the sole parent of that idea. The third thing is love, which proceeds from the mind itself and from its idea, as the mind knows itself and loves itself. It could not love itself unless it knew itself. It loves its beloved offspring, its idea of itself; so love is a kind of joining of parent and offspring. See in these words how there appears a certain ‘vestige’ of the Trinity."