When we confess that He was buried, we do not make this, as it were, a distinct part of the Article, as if it presented any new difficulty which is not implied in what we have said of His death; for if we believe that CHRIST DIED, we can also easily believe that He was buried. The word buried was added in the Creed, first, that His death might be rendered more certain, for the strongest argument of a person’s death is the proof that his body was buried; and, secondly, to render the miracle of His Resurrection more authentic and illustrious.
It is not, however, our belief that the body of Christ alone was interred. The above words propose, as the principal object of our belief, that God was buried; as according to the rule of Catholic faith we also say with the strictest truth that GOD DIED, and that God was born of a virgin. For as the Divinity was never separated from His body which was laid in the sepulchre, we truly confess that God was buried.
(Catechism of the Council of Trent, Article IV, Christ Was Really Buried, Part 2)
The second divine person did not cease to exist after His death on the cross but only experienced death by separation of soul and body. The God head which is the divine nature can never die and that is the same with the human nature because natures are only abstract and can never experience and do actions. The 2nd divine person possesses the God head which is the divine nature because a person can never be a person without nature. The second divine person died in (by or through) His human nature because he became flesh. Jesus must never be regarded as a human person. The second divine person is God therefore God died. God literally died.
CCC624 “By the grace of God” Jesus tasted death “for every one”.459 In his plan of salvation, God ordained that his Son should not only “die for our sins”460 but should also “taste death”, experience the condition of death, the separation of his soul from his body, between the time he expired on the cross and the time he was raised from the dead. The state of the dead Christ is the mystery of the tomb and the descent into hell. It is the mystery of Holy Saturday, when Christ, lying in the tomb,461 reveals God’s great sabbath rest462 after the fulfillment463 of man’s salvation, which brings peace to the whole universe.464
The brilliant and renowned apologist Bro. Socrates Fernandez who was present in the Catholic Faith Defenders 40th National Convention in Siena College, Quezon city himself in his book defined the difference of nature and person with help from a source. He asked Bishop Teodoro Bacani about the issue and the Bishop answered Bro. Socrates C. Fernandez in a ways that lay apologists will understand. Bishop Bacani emphasized that nature belongs to a person just like our hands because the actions of the hands is rooted from nature and the actions of the hands, we must understand is done by a person who possesses nature.
“Nature is a term related to essence that makes a thing, a thing. For instance, the nature of man is that he has a body and soul. If it is only the body, without any soul, it cannot be called man in the strictest sense of the word. Therefore nature is synonymous to essence which makes a thing what it is. If heat, light and color are taken away from fire, it will no longer be called fire but some other thing. So, that is nature or essence which makes a thing being called for what it is. Nature-n, the character or constitution or essential traits of a person or thing or class especially if original rather than acquired (New Standard College Dictionary, Page 790)
It is Nature which answers the question WHAT IS THAT? Just as we say that this is an animal, or plant or man.
Now, we shall start tracing the meaning of the word PERSON. Person is a being that has mind and free will. Person answers the question WHO IS THAT? It does not mean that every person is that who has a body, or that every bodily for is called person. It is not so because horse and the plant have bodies yet they are not considered person. Even if there are no material parts as long as there is mind and free will then that being can be considered a person. Angels are spirits; they don´t have material parts even though they are capable of appearing materially through bodily forms, yet in their very being they don´t have material parts. Angels are considered persons because they have mind and free will.”
(Defense: Catholic Truth by Bro. Socrates C. Fernandez, PAGE 11)
Christ (the second divine person), the immortal God Himself testified about His death
Revelation 1:8King James Version (KJV)
8 I am Alpha and Omega, the beginning and the ending, saith the Lord, which is, and which was, and which is to come, the Almighty.
Revelation 1:17-18King James Version (KJV)
17 And when I saw him, I fell at his feet as dead. And he laid his right hand upon me, saying unto me, Fear not; I am the first and the last:
18 I am he that liveth, and was dead; and, behold, I am alive for evermore, Amen; and have the keys of hell and of death.
Revelation 2:8King James Version (KJV)
8 And unto the angel of the church in Smyrna write; These things saith the first and the last, which was dead, and is alive;