What Christians Believe

The Athanasian Creed states,

Whoever wishes to be saved must, above all, keep the Catholic faith. For unless a person keeps this faith whole and entire, he will undoubtedly be lost forever. This is what the catholic faith teaches: we worship one God in the Trinity and the Trinity in unity. Neither confounding the Persons, nor dividing the substance. For there is one Person of the Father, another of the Son, another of the Holy Spirit.

But the Father and the Son and the Holy Spirit have one divinity, equal glory, and coeternal majesty. What the Father is, the Son is, and the Holy Spirit is.

The Father is uncreated, the Son is uncreated, and the Holy Spirit is uncreated. The Father is boundless, the Son is boundless, and the Holy Spirit is boundless. The Father is eternal, the Son is eternal, and the Holy Spirit is eternal.

Nevertheless, there are not three eternal beings, but one eternal being. So there are not three uncreated beings, nor three boundless beings, but one uncreated being and one boundless being. Likewise, the Father is omnipotent, the Son is omnipotent, the Holy Spirit is omnipotent.

Yet there are not three omnipotent beings, but one omnipotent being. Thus the Father is God, the Son is God, and the Holy Spirit is God.

However, there are not three gods, but one God. The Father is Lord, the Son is Lord, and the Holy Spirit is Lord. However, there are not three lords, but one Lord. For as we are obliged by Christian truth to acknowledge every Person singly to be God and Lord, so too are we forbidden by the Catholic religion to say that there are three Gods or Lords.

The Father was not made, nor created, nor generated by anyone. The Son is not made, nor created, but begotten by the Father alone. The Holy Spirit is not made, nor created, nor generated, but proceeds from the Father and the Son. There is, then, one Father, not three Fathers; one Son, not three sons; one Holy Spirit, not three holy spirits. In this Trinity, there is nothing before or after, nothing greater or less. The entire three Persons are coeternal and coequal with one another. So that in all things, as is has been said above, the Unity is to be worshiped in Trinity and the Trinity in Unity.

He, therefore, who wishes to be saved, must believe thus about the Trinity. It is also necessary for eternal salvation that he believes steadfastly in the incarnation of our Lord Jesus Christ. Thus the right faith is that we believe and confess that our Lord Jesus Christ, the Son of God, is both God and man. As God, He was begotten of the substance of the Father before time; as man, He was born in time of the substance of His Mother. He is perfect God; and He is perfect man, with a rational soul and human flesh. He is equal to the Father in His divinity, but inferior to the Father in His humanity. Although He is God and man, He is not two, but one Christ. And He is one, not because His divinity was changed into flesh, but because His humanity was assumed unto God. He is one, not by a mingling of substances, but by unity of person. As a rational soul and flesh are one man: so God and man are one Christ. He died for our salvation, descended into Hell, and rose from the dead on the third day. He ascended into Heaven, sits at the right hand of God the Father almighty. From there He shall come to judge the living and the dead. At His coming, all men are to arise with their own bodies; and they are to give an account of their own deeds. Those who have done good deeds will go into eternal life; those who have done evil will go into the everlasting fire.

This is the Catholic faith. Everyone must believe it, firmly and steadfastly; otherwise He cannot be saved. Amen.

Why Christians Believe This

We believe what we believe because we place our faith in the Church whose Sacred Scripture is replete with proofs of the Trinity!  (see relevant Scripture with commentary below) In the Old Testament, from the very first chapter of Genesis, when God says, "Let US make man in OUR image," to God's use of two different persons in Malachi 3:1, each and every Book of the Old Testament (Tanach) speaks of the triune nature of our God. Isaiah, in the 9th chapter and 6th verse of his book, very clearly predicts that the Messiah will be called "a Mighty GOD" -- and the Gospels make clear that's Who Messiah is! From the Catholic Encyclopedia:

• He declares that He will come to be the judge of all men (Matthew 25:31). In Jewish theology the judgment of the world was a distinctively Divine, and not a Messianic, prerogative.  
  

• In the parable of the wicked husbandmen, He describes Himself as the son of the householder, while the Prophets, one and all, are represented as the servants (Matthew 21:33 sqq.).  
  

• He is the Lord of Angels, who execute His command (Matthew 24:31).  

• He approves the confession of Peter when he recognizes Him, not as Messias -- a step long since taken by all the Apostles -- but explicitly as the Son of God: and He declares the knowledge due to a special revelation from the Father (Matthew 16:16-17).  
  

• Finally, before Caiphas He not merely declares Himself to be the Messias, but in reply to a second and distinct question affirms His claim to be the Son of God. He is instantly declared by the high priest to be guilty of blasphemy, an offense which could not have been attached to the claim to be simply the Messias (Luke 22:66-71).

At His Baptism, the Three Persons were manifest at once:

Matthew 3:13-17
Then cometh Jesus from Galilee to Jordan unto John, to be baptized of him. But John forbad him, saying, I have need to be baptized of thee, and comest thou to me? And Jesus answering said unto him, Suffer it to be so now: for thus it becometh us to fulfil all righteousness. Then he suffered him. And Jesus, when he was baptized, went up straightway out of the water: and, lo, the heavens were opened unto him, and he saw the Spirit of God descending like a dove, and lighting upon him: And lo a voice from heaven, saying, This is my beloved Son, in whom I am well pleased.

And the "Great Commission" to evangelize and baptize is crystal clear in naming the Three Persons:

Matthew 28:19
Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit.

The most common argument against the divinity of Christ (as opposed to His "mere" Messiah-ship) revolves around the Sh'ma (or "shema"), Deuteronomy 6:4, which reads, "Hear, O Israel: The LORD our God is one LORD" First, no Catholic doubts that God is one God! Second, the point of the verse is to emphasize that the ancient Israelites worshipped the true God as opposed to false, pagan, polytheistic gods. The text in Hebrew would read better as "Hear, O Israel: God is our God; God is One." Thirdly, the relevant Hebrew words include:

• YHWH, singular name for the Godhead
• Elohim, which is the plural of Eloah, or "God"
• echad, which usually indicates a composite, such as "a flock" (singular) of geese (plural) or "a bunch" (singular) of grapes (plural)

But How Can a Man be God?

From the New Testament, some argue that Jesus wept, and ate, and slept -- how could He possibly be God? Humans can't be God! Mystery of mysteries! Jesus Himself told us He didn't expect us to easily understand (Philippians 2:6)! He took on a human nature. And He is divine, His humanity and divinity being in complete and perfect hypostasis. To believe this is not possible is sheer anthropomorphism; it is to limit God and try to "box Him in" to human understanding and daily experience. Humans can't be God? OK. But God can -- and did -- take on a human nature, just as Isaiah predicted:

Isaiah 9:6
For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty GOD, The everlasting Father, The Prince of Peace.

...and a man named Jesus walked out of His grave 2,000 years ago (see Shroud of Turin).
 

Understanding the Trinity (well, almost!)

In some ways we might not ever truly understand the Trinity, at least while we're on earth. It seems so paradoxical, so illogical to those who think of the Three Divine Persons as Three separate "Beings": 1+1+1=3? Yes! But change your operators -- 1X1X1=1! We have to loosen up our minds a little, and think in terms of Essences, not separate ontological realities. God is one Essence; He is "Being" itself. He is He Who called Himself "I AM." The Three Persons are of this same Divine Essence; they are the same Being, and are only distinct in Their relations with One Another.

But more interesting than this is one explanation of WHY God is in Three Persons -- and this is where things get good.
 

God is Love

Christians say all the time that "God is Love". Oh, and it's so true! And it is this understanding that can give us a foothold in our attempt to understand this Mystery because love needs an object. You can't love if there's no one (or No One) to love! The Father isn't in Heaven eternally loving Himself; He has the Son. And the Son has the Father. And they have the Spirit, Who has Them. The Godhead must be triune because:

• God is Love;
• Love needs an object;
• God is self-sufficient and needs no one outside of God;
• Love is ever creative, abundant and life-giving! From Love proceeds Love!

The Father-Monarch did not create the Son, He begat Him. He did not create the Spirit, the Spirit proceeds from Him and the Son. But all this takes place outside of time, in God's dimension: He is triune eternally, from the beginning, and is complete in Himself.

There have been many attempts to symbolize the Trinity to make God understandable to us: St. Patrick used the shamrock, some use the three states of water to show that liquid water, steam, and ice all have the same essence (H₂0) while being three easily-identified entities.

But perhaps the best way to symbolize and think of the Trinity is to consider the human family. The family is an icon of the Trinity, being made in the image of the God, joining together as man and wife and becoming one flesh, and helping God bring new life into the world. This reflects beautifully the endless Love that is our triune God. Distinct persons, one family... Say there's a family whose last name is Caruso: each person of the Caruso family is fully, 100% "Caruso"; not a one of them is any less or more Caruso than another member of the Caruso family, though there are the Caruso father and the Caruso mother and the Caruso children. Each of these Carusos is a different person -- but the Caruso family is ONE family.

It is the same with God the Father, God the Son, and God the Holy Spirit! Each is God, not One is less God than another: three Persons, one God, one Being, one Divine Essence.

This analogy of "family" has its definite limitations (there is inequality in human families, but no inequality among the Divine Persons, so please keep that in mind); nonetheless, the analogy is the best I've heard. Gloria in excélsis Deo!