"by Scripture alone"
It is from the Bible alone that believers derive their theology. Not from church tradition. We believe what we believe because we find it in the Bible. The Church is to be the pillar and support of the the truth, and that is found in the Bible alone.
"by Christ alone"
Salvation was accomplished exclusively by Christ alone through his death to save sinners. Christ alone is the Saviour of sinners. Christ alone is the object of the sinner's faith. This establishes the exclusivity of the gospel of Jesus Christ ~ Christ alone saves!
"by Faith alone"
This is the pivotal truth that stood at the centre of the Reformation. The Reformers referred to this as "the material principal", because it involves the very heart of what a sinner must do to be saved. No amount of human goodness could ever merit eternal life. Faith alone saves!
"by Grace alone"
Salvation is not a reward for the righteous, but a gift for the guilty. sinners have no claim upon God. God owes them nothing but judgement for their sins. If God saves any, it is in spite of them, not because of them. Grace is given to those who cannot earn it. Grace alone saves.
Soli Deo Gloria:
"to the glory of God alone"
Only a salvation that is by grace alone through faith alone in Christ alone based on the Scripture alone can bring glory to God alone. The entirety of Scripture - the story of redemption that is the Bible - is given to reveal a God who alone is most worthy to be praised. The highest purpose in all God does is to promote and magnify His glory for the joy of His people.
On these "five solas" I draw my line in the sand.
"God is most glorified in you, when you are most satisfied in Him."
Love in the Truth.