“For it is by grace you have been saved, through faith—and this is not from yourselves, it is the gift of God not by works, so that no one can boast.” (Eph 2:8-9)
Reformed theology is not a departure from (nor an aberration of) Christianity, but a refined focus on Christianity itself through embracing of the scriptures as the only necessary and sufficient authority on the word of God. Reformed theology is both catholic and orthodox, in that it is formed from the teaching of both Jesus and His designated apostles. Like many denominations, Reformed theology believes:
There is a Sovereign and Triune God
God is eternally existent in three distinct entities: God the Father, Jesus the Son, and the Holy Spirit. Even though they are separate in consciousness, they are the same in essence. Jesus existed before the foundation of the Earth, he was firstborn of every creature (Col 1:15) and is the very essence of God (John 1:1).
Matt. 3:16–17: As soon as Jesus was baptized, he went up out of the water. At that moment heaven was opened, and he saw the Spirit of God descending like a dove and alighting on him. And a voice from heaven said, “This is my Son, whom I love; with him I am well pleased.”
Matthew 28:19: Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit.
1 John 5:6-8: It is the Spirit that beareth witness, because the Spirit is truth. For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one. And there are three that bear witness in earth, the spirit, and the water, and the blood: and these three agree in one.
Jesus Christ was the Word of God who had Become Flesh
With Him He brought the Gospel, ushering in and fulfilling the New Covenant by His death on the cross. Once Christ had ascended, the Holy Spirit revealed itself to men, the Spirit of Truth.
John 1:1-14 In the beginning was the Word, and the Word was with God, and the Word was God. He was with God in the beginning. Through him all things were made; without him nothing was made that has been made. In him was life, and that life was the light of all mankind. The light shines in the darkness, and the darkness has not overcome it.
The true light that gives light to everyone was coming into the world. He was in the world, and though the world was made through him, the world did not recognize him. He came to that which was his own, but his own did not receive him. Yet to all who did receive him, to those who believed in his name, he gave the right to become children of God— children born not of natural descent, nor of human decision or a husband’s will, but born of God.
The Word became flesh and made his dwelling among us. We have seen his glory, the glory of the one and only Son, who came from the Father, full of grace and truth.
John 14:17: “If you love me, keep my commands. And I will ask the Father, and he will give you another advocate to help you and be with you forever— the Spirit of truth. The world cannot accept him, because it neither sees him nor knows him. But you know him, for he lives with you and will be in you.
The Church is the Body of Christ:
These are the people who were saved through faith in Jesus and blessed with the Holy Spirit. These Christians are God’s chosen people, who He foreknew, and His Law is written on their hearts.
Romans 12:4-5: For as in one body we have many members, and the members do not all have the same function, so we, though many, are one body in Christ, and individually members one of another.
1 Corinthians 12:13: For in one Spirit we were all baptized into one body—Jews or Greeks, slaves or free—and all were made to drink of one Spirit.
Hebrews 10:15-17: And the Holy Spirit also bears witness to us; for after saying, “This is the covenant that I will make with them after those days, declares the Lord: I will put my laws on their hearts, and write them on their minds,” then he adds, “I will remember their sins and their lawless deeds no more.”
Ephesians 1:4-6: For He chose us in Him before the foundation of the world to be holy and blameless in His presence. In love He predestined us for adoption as His sons through Jesus Christ, according to the good pleasure of His will to the praise of His glorious grace, which He has freely given us in the Beloved One.
The Existence of Sacraments
Reformed theology accepts and practices sacraments, such as confession and baptism. Although the scriptural process of regeneration differs from those oft established in orthodox and Roman Catholic traditions, there are still acts of faith specifically wanted by God.
James 5:16: Therefore confess your sins to each other and pray for each other so that you may be healed. The prayer of a righteous person is powerful and effective.
Peter 3:21-22: And this water symbolizes the baptism that now saves you also—not the removal of dirt from the body, but the pledge of a clear conscience toward God—through the resurrection of Jesus Christ.
The Inerrancy and Divine Authorship of the Original Scriptures:
The New Testament books in the Protestant Bibles were those that were verifiably written by the apostles, and/or considered to be legitimate sources by foundational leaders of the Early Church. Much of the cohesion of the criteria of acceptance of the above two metrics come from the fact that prominent Early Church leaders included the apostles themselves. They are also the same books as those held in the Roman Catholic’s New Testament due to both denominations sharing forerunners.
The Old Testament, of course, was already verified and codified scripture in the time of Christ. The Apocryphal books, which do not claim divine authorship, are not included. Notably they were also rejected by the original compiler of the Latin Vulgate, Saint Jerome on the same grounds (a).
2 Tim. 3:16: All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness.
1 Cor. 4:6: Brothers, I have applied these things to myself and Apollos for your benefit, so that you may learn from us not to go beyond what is written.
1 Peter 1:25: But the word of the Lord remains forever.” And this word is the good news that was preached to you.
The Purpose of the Reformation
The Reformation was born out of dissatisfaction with the extra-biblical teachings that progressively grew within the Catholic denomination. If the original scripture, especially the Word spoken by Jesus in the Gospel and expatiated by His chosen apostles was inerrant and sufficient, then any new traditions and laws were unnecessary at best or confounding at worst. The Reformation was a separation from extra-biblical laws and traditions, not the scriptures. It was not born out of ignorance to scripture, but of increased understanding and dedication to them.
Acts 20:26-30: Therefore I testify to you this day that I am innocent of the blood of all, 27 for I did not shrink from declaring to you the whole counsel of God. Pay careful attention to yourselves and to all the flock, in which the Holy Spirit has made you overseers, to care for the church of God, which he obtained with his own blood. I know that after my departure fierce wolves will come in among you, not sparing the flock; and from among your own selves will arise men speaking twisted things, to draw away the disciples after them.
Matthew 15:8-9: 8‘These people honor me with their lips, but their hearts are far from me. They worship me in vain; their teachings are merely human rules.” (Jesus to the Pharisees)
Hebrews 1:1-2 Long ago, at many times and in many ways, God spoke to our fathers by the prophets, 2 but in these last days he has spoken to us by his Son, whom he appointed the heir of all things, through whom also he created the world.
Colossians 2:8: See to it that no one takes you captive by philosophy and empty deceit, according to human tradition, according to the elemental spirits of the world, and not according to Christ.
In this regard, Reformed Theology elevates the original scripture as the sovereign authority on salvation and Christian living. This isn’t to say all other insight from other people is to be rejected, only that is never to be equal or capable of amending the scriptures. Reformed Christianity does not have any extra-biblical traditions, their Catechism is the Bible itself.
Sources
(a) A Brief History of the Apocrypha: https://faculty.wts.edu/posts/a-brief-history-of-the-apocrypha/