The gospel is the good news that God came to Earth as the human Jesus in order to save some from judgement of their sins, redeem them from slavery to sin and will come again to institute His new Kingdom. The life, death and resurrection of Jesus is the lens through which we understand Scripture, view the world and conduct our lives.
During the Reformation several phrases epitomised Protestant understanding, each involving the word Alone or Only. Five of them were compiled together as a summary of distinctive Protestantism by Metz in 1965 but each phrase was coined individually in the 1500s and subsequently published in groups of two, three or four. These statements were designed to match the four Aristotelian causes: Material (substance of a thing), Formal (a thing’s layout or plan), Efficient (the actions to create a thing) and Final (the purpose of a thing). After Aristotle, the Instrumental cause (tool used to create a thing) was theorised and in the Roman church equates to the role of the priest at Mass and administering sacraments where the principal agent (Efficient cause) is Jesus Christ.
“Sola Dei Verbum” (which includes tradition) is rejected by Protestants but “solo verbo” and “sola experientia” are agreed within the Western Church. The five below distinguish Protestant belief.
This is the material cause of The Reformation: The doctrine by which the Protestant church stands or falls. Faith is the substance of the born again believer.
The Bible is the formal cause of the Reformation and the source of the material principle: The Gospel of Jesus Christ. The Bible contains God’s formal plan for humans, given to us by special revelation.
This is the doctrine of Monergism in Salvation, that God alone saves a sinner and His action equates to the efficient cause.
This means that saints and angels are not worthy of the glory given to them since their good works were authored and sanctified by God. Good religious men are honoured because of the glory they gave to God and in honouring them we also honour God for His goodness in creating them.
This equates to the final cause, the purpose of human existence which is to glorify God and enjoy Him forever.
This does not easily equate to the instrumental cause as Christ is no mere tool but rather He is the ground of Salvation as the only Mediator (cause materia) and Saviour (causa impulsiva) of sinners.