The Five 'Solas'

As Luther studied the Psalms, and the books of Hebrews, Romans and Galatians, he came to view the use of terms penance and righteousness by the Catholic Church in a new light. He felt that the Church had lost what he saw were several central truths of Christianity and had become corrupt. He became particularly focused on the idea of justification. He wrote “that is why faith alone makes someone just and fulfils the law. Faith is that which brings the Holy Spirit through the merits of Christ.” Luther’s doctrine of justification- God’s act of declaring a sinner righteous- was by faith alone through God’s grace. Luther explained his concept of Justification in the Smalcald Articles: 

“The first and chief article is this: Jesus Christ, our God and Lord, died for our sins and was raised again for out justification (Romans 3:24-25). He alone is the Lamb of God who takes away the sins of the world (John 1:29), and God has laid on Him the iniquity of us all (Isaiah 53:6). All have sinned and are justified freely, without their own works and merits, by His grace, through the redemption that is in Christ Jesus, in His blood (Romans 3:23-25). This is necessary to believe.”

In effect, this constituted a repudiation of papal and ecclesiastical authority in favour of the Bible (sola Scriptura).

Sola Scriptura

The Latin literally means "scripture alone," typifying the Protestant belief that only scripture is valid for the derivation of doctrine. Church Fathers, Popes, Priests, Saints, etc. have no special authority to determine what is true doctrine nor to interpret the Bible authoritatively. Key source texts for this are Acts 17:11 where the Berean Jews study the scriptures fervently in anticipation of the arrival of an apostle. Equally, 2 Timothy 3:15-17 describes all scripture as "god-breathed" and useful for teaching, instructing, rebuking, etc. Isaiah 8:20 indicates how the faithful should speak only according to God's word.

Sola Fide

The Latin literally means "faith alone," typifying the Protestant belief that only faith is necessary for salvation. Good works, attending church or participating in ceremonies do not "earn" salvation and have no bearing on whether one will attain eternal life. Key source texts for this are Romans 3:28 which indicates that people are made right with God through faith, not through works of the Jewish law. Galatians 2:15 gives similar sentiments. Ephesians 3:12 discusses the freedom and confidence with which the faithful may approach God. 

Sola Gratia

The Latin means "by grace alone," typifying how it is by the goodness of good, not personal effort, that Christians are saved. God does not owe us salvation but gives it as his free gift. Key texts for this are Ephesians 2:8-9, which indicates that faith itself is not from ourselves, but it is a gift from God. Romans 11:6 shows how faith itself cannot be considered a "work," otherwise it would not be a manifestation of grace. Titus 3:5 shows how God's grace was given not as a response to our goodness, but despite our depravity. 

Solus Christus

The Latin means "Christ alone," showing how Christ only is the mediator between humans and God, not priests or any clergy. Moreover, salvation is actuated by Christ alone in his sacrificial death, not through any human action. Key texts from this are Act 4:12, which indicates how salvation is found in "no other name" than Christ. In John 14:6, Jesus claims he himself is the exclusive path to salvation. 1 Timothy 2:5 demonstrates the exclusivity of Christ's role as mediator, for whom there is no substitute. 

Soli Deo Gloria

The Latin means "to the glory of God alone," indicating how all things, particularly salvation, serve the purpose of glorifying God. Key texts for this are Romans 11:36 which states how all things are "from him and through him and for him," namely God, in a classic Pauline doxology. 1 Corinthians 10:31 states how all human activities can be subordinated to God as forms of worship. Psalm 115:1 states how all wordly glory points to God, not mankind.