In the second article found in the Catechetical Instructions of St. Thomas Aquinas, he speaks about Jesus Christ, His only Son, our Lord.
Here is where we have a complete separation from our Jewish and Muslim brethren.
St. Thomas writes, “It is not only necessary for Christians to believe in one God who is Creator of heaven and earth and of all things, but also they must believe that God is Father and Christ is true Son of God.
“This, as St. Peter says, is not mere fable, but is certain and proved by the word of God on the Mount of Transfiguration. (Quoting 2 Peter 1:16-19) ‘For we did not follow cleverly devised myths when we made known to you the power and coming of our Lord Jesus Christ, but we were eyewitnesses of his majesty. For when he received honor and glory from God the Father and the voice was borne to him by the Majestic Glory, ‘This is my beloved Son, with whom I am well pleased,’ we heard this voice borne from heaven, for we were with him on the holy mountain.’”
This is the second theophany (a sensible manifestation of the Trinity) and occurs at what was traditionally known as Mt. Tabor. The first theophany (voice from heaven, dove, Jesus) was the Baptism of our Lord by John the Baptist.
A couple of things to note. Witness testimony. When Peter refers to “we,” the others are James and John (sons of Zebedee). When you read the Gospel of John, you should notice the number of times he refers to a person’s testimony about their experience of God. Your testimony is crucial because as St. Paul says in Romans 10:17, “ … faith comes from what is heard … ” and St. Peter says in 1 Peter 3:15, “ … Always be prepared to make a defense to anyone who calls you to account for the hope that is in you … ”
The second is a bit trickier. Talk to any Christian and they would say or believe that Jesus Christ is their Lord and Savior. End of story.
The issues/problems begin to manifest when people begin talking about who Jesus is and his relation to God. It is important that we not only believe that Jesus is our Lord and Savior but that we have the truth about who Jesus and God is as revealed by God. One may assert that the Gospel writer John wrote what he did when he did (90s A.D.) because he wanted no confusion on that point after doubts may have arisen as to the nature of Jesus.
What are some of the errors that St. Thomas cites? These errors (which occurred before Protestantism) are still held today by some who call themselves Christian and who would say that Jesus Christ is their Lord and Savior.
Photinus (fourth century bishop) believed that Christ is not the Son of God but lived such a good life that he merited adoption and to be called son of God.
Sabellius (third century priest/theologian) believed that the Father Himself became incarnate and, therefore, the Father and the Son is the same Person.
Arius (third/fourth century priest). He is the reason the Nicene Creed is read because his is a persistent (still held) error. Arius, although he would say that Christ was before (temporally) the Blessed Virgin and that the Person of the Father is other than the Person of the Son, nevertheless made a three-fold attribution to Christ: (1) that the Son of God was a creature; (2) that He is not from eternity but was formed the noblest of all creatures in time by God; (3) that God the Son is not of one nature with God the Father, and therefore that He was not true God.
St. Paul uses the word “mystery” when trying to explain something. God was not so mysterious that He didn’t reveal certain truths.
One could give many reasons why it is important to believe what the Church teaches about Jesus. I believe no. 143 in the Catechism of the Catholic Church encapsulates it. “By faith, man completely submits his intellect and his will to God. With his whole being man gives his assent to God the revealer. Sacred Scripture calls this human response to God, the author of revelation, “the obedience of faith.”
We must admit and be humble that our knowledge, understanding and language is limited when it comes to God. St. Paul writes in 1 Tim 3:15, “if I am delayed, you may know how one ought to behave in the household of God, which is the Church of the living God, the pillar and bulwark of the truth.”
The Church has us recite the Nicene Creed at every Sunday Mass so we don’t forget the truth. Trust THE Catholic Church, the pillar and bulwark of the truth.