The Five Solas are five Latin phrases (or slogans) that emerged from the Protestant Reformation intended to summarize the Reformers' basic theological principles in contrast to certain teachings of the Roman Catholic Church of the day. "Sola" is Latin meaning "alone" or "only" and the corresponding phrases are:
• Sola Fide, by faith alone.
• Sola Scriptura, by Scripture alone.
• Solus Christus, through Christ alone.
• Sola Gratia, by grace alone.
• Soli Deo Gloria, glory to God alone.
These phrases may be found individually expressed in the various writings of the 16th century Reformers, either explicitly or implicitly, but they are not found presented as a list per se. It is most likely the list of Solas came about later.
The following summary of the Five Solas is adapted from The Cambridge Declaration of the Alliance of Confessing Evangelicals (1996):
Faith alone (Sola Fide)
Justification is by grace alone through faith alone because of Christ alone. In justification Christ's righteousness is imputed to us as the only possible satisfaction of God's perfect justice. Our justification does not rest on any merit to be found in us, nor upon the grounds of an infusion of Christ's righteousness in us, nor that an institution claiming to be a church that denies or condemns sola fide can be recognized as a legitimate church.
Scripture alone (Sola Scriptura)
The inerrant Scripture (the Bible) is the sole source of written divine revelation, which alone can bind the conscience. The Bible alone teaches all that is necessary for our salvation from sin and is the standard by which all Christian behavior must be measured. It is denied that any creed, council or individual may bind a Christian's conscience, that the Holy Spirit speaks independently of or contrary to what is set forth in the Bible, or that personal spiritual experience can ever be a vehicle of revelation.
Christ alone (Solus Christus)
Our salvation is accomplished by the mediatorial work of the historical Christ alone. His sinless life and substitutionary atonement alone are sufficient for our justification and reconciliation to the Father. It is denied that the gospel is preached if Christ's substitutionary work is not declared and faith in Christ and his work is not solicited.
Grace alone (Sola Gratia)
In salvation we are rescued from God's wrath by his grace alone. It is the supernatural work of the Holy Spirit that brings us to Christ by releasing us from our bondage to sin and raising us from spiritual death to spiritual life. It is denied that salvation is in any sense a human work. Human methods, techniques or strategies by themselves cannot accomplish this transformation. Faith is not produced by our unregenerated human nature.
Glory to God alone (Soli Deo Gloria)
It is affirmed that because salvation is of God and has been accomplished by God, it is for God's glory and that we must glorify him always. We must live our entire lives before the face of God, under the authority of God and for his glory alone. It is denied that we can properly glorify God if our worship is confused with entertainment, if we neglect either Law or Gospel in our preaching, or if self-improvement, self-esteem or self- fulfillment are allowed to become alternatives to the gospel.
To read the declaration in its entirety click here.