The Catholic Church bases her teaching upon one source: The word of God. This divine revelation is transmitted in two ways: through Scripture and apostolic tradition. Many assume that only the writings of the apostles are the word of God. However, their oral transmission of the faith is also considered the word of God (1 Thess. 2:13). Few Protestant groups today accept the validity, let alone the authority, of tradition. In fact, many believe that Scripture is the only definitive source of divine truth. For this reason, they are critical of certain doctrines of the Catholic Church, which, according to them, have no basis in Scripture. In fact, those who embrace the theory of sola scriptura attempt to use the Bible to contradict, to prove baseless, certain Church teachings, such as the Real Presence and the existence of purgatory.



The Trinity



"Then God said, ‘Let us make man in our image, after our likeness . . .’" (Gen. 1:26).

"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" (Matt. 28:19).

"In the beginning was the Word, and the Word was with God, and the Word was God." (John 1:1)

"But Peter said, ‘Ananias, why has Satan filled your heart to lie to the Holy Spirit and to keep back part of the proceeds of the land? While it remained unsold, did it not remain your own? And after it was sold, was it not at your disposal? How is it that you have contrived this deed in your heart? You have not lied to men but to God.’" (Acts 5:3-4)

"The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all" (2 Cor. 13:14).



Real Presence in the Eucharist



"‘Truly, truly, I say to you, he who believes has eternal life. I am the bread of life. Your fathers ate the manna in the wilderness, and they died. This is bread which comes down from heaven, that a man may eat of it and not die. I am the living bread which came down from heaven; if any one eats of this bread, he will live for ever; and the bread which I shall give for the life of the world is my flesh.’ The Jews then disputed among themselves, saying, ‘How can this man give us his flesh to eat?’ So Jesus said to them, ‘Truly truly, I say to you, unless you eat the flesh of the Son of man and drink his blood, you have no life in you; he who eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day. For my flesh is food indeed, and my blood is drink indeed’" (John 6:47-55).

"For I received from the Lord what I also delivered to you, that the Lord Jesus on the night when he was betrayed took bread, and when he had given thanks, he broke it, and said, ‘This is my body which is for you. Do this in remembrance of me.’ In the same way also the cup, after supper, saying, ‘This cup is the new covenant of my blood. Do this, as often as you drink it, in remembrance of me.’ For as often as you eat this bread and drink the cup, you proclaim the Lord’s death until he comes" (1 Cor. 11:23-26).

"Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of profaning the body and blood of the Lord" (1 Cor. 11:27).



Purgatory



"For if he were not expecting that those who had fallen would rise again, it would have been superfluous and foolish to pray for the dead. But if he was looking to the splendid reward that is laid up for those who fall asleep in godliness, it was a holy and pious thought. Therefore he made atonement for the dead, that they might be delivered from their sin" (2 Macc. 12:44-45).

"Make friends quickly with your accuser, while you are going with him to court, lest your accuser hand you over to the judge, and the judge to the guard, and you be put in prison; truly, I say to you, you will never get out till you have paid the last penny" (Matt. 5:25-26).

"Each man’s work will become manifest; for the Day will disclose it, because it will be revealed with fire, and the fire will test what sort of work each one has done. If the work which any man has built on the foundation survives, he will receive a reward. If any man’s work is burned up, he will suffer loss, though he himself will be saved, but only as through fire" (1 Cor. 3:13-15).

"For Christ also died for sins once for all, the righteous for the unrighteous, that he might bring us to God, being put to death in the flesh but made alive in the spirit; in which he went and preached to the spirits in prison, who formerly did not obey . . ." (1 Peter 3:18-20).

"But nothing unclean shall enter it [heaven] . . ." (Rev. 21:27).

Honor Due to the Virgin Mary



"And when Elizabeth heard the greeting of Mary, the babe leaped in her womb, and Elizabeth was filled with the Holy Spirit and she exclaimed with a loud cry, ‘Blessed are you among women and blessed is the fruit of your womb! And why is this granted me, that the mother of my Lord should come to me?’" (Luke 1:41-43).

"And Mary said, ‘My soul magnifies the Lord, and my spirit rejoices in God my Savior, for he has regarded the low estate of his handmaiden. For behold, henceforth all generations will call me blessed; for he who is mighty has done great things for me, and holy is his name’" (Luke 1:46-49).

"If one member suffers, all suffer together; if one member is honored, all rejoice together" (1 Cor. 12:26).


Praying to the Saints



"‘And as for the dead being raised, have you not read in the book of Moses, in the passage about the bush, how God said to him, "I am the God of Abraham, and the God of Isaac, and the God of Jacob"? He is not God of the dead, but of the living . . .’" (Mark 12:26-27)

"Therefore, since we are surrounded by so great a cloud of witnesses, let us also lay aside every weight, and sin which clings so closely . . ." (Heb. 12:1).

"And when he had taken the scroll, the four living creatures and the twenty-four elders fell down before the Lamb, each holding a harp, and with golden bowls full of incense, which are the prayers of the saints" (Rev. 5:.

Source: https://www.catholic.com/tract/scriptural-reference-guide-0