The Reformers didn’t sit down one day and come up with the sola sayings. However, these solas were still a significant emphasis of the Reformation. There are five solas (sola meaning “only” or “alone”).
The first is sola Scriptura, or “Scripture alone.” This means that only scripture has the authority to speak from God because it comes from God. We can think of the church like a teacher. It teaches us scripture but must still submit to the authority and content of scripture. It does not have any authority in and of itself outside of the authority that teaching the Word of God gives it.
The second is solo Christo, or “Christ alone.” This means that Jesus Christ is the only mediator between God and sinful humanity. It is only by Christ that our sins are taken away and we have any righteousness or goodness before God. Only through Christ Jesus do we have reconciliation with God the Father. Christ bridges the gap between God and sinful humanity by taking on the debt and curse of sin for us.
The third is sola fide, or “faith alone.” This means that only by faith in Christ do we have any salvation. We cannot earn anything by our own efforts or good works. Instead, it is only by believing in Jesus and depending upon Jesus’ righteousness that we can be saved from sin and death. Jesus earned good works in our place and gives them freely to us, like credit to our account.
The fourth is sola gratia, or “grace alone.” This means that salvation is only by God’s grace to us. That is, we do not and cannot deserve God’s salvation by our good works. God sent his Son Jesus to do what we could not do and through Jesus offers us undeserved salvation for free.
Soli Deo Gloria
The fifth is soli Deo gloria, “God’s glory alone.” This means that everything we do and believe is for the glory of God only and not for the glory of self or men.
The fact that God comes near to us in forgiveness and in grace through Christ was really at the heart of the Reformation. We are made right before God only because of the work Jesus has accomplished for us. Good works follow as fruit grows from a tree.
At the time of the Reformation, the medieval church (what we now think of as the Roman Catholic Church) also believed Scripture had authority, that people needed to have faith in Christ, and that grace was necessary, but they missed the “only” part. They added or defined each of these things to mean something not found in the Bible and this is why we need to recover the emphasis of the Reformation solas to this very day.