Sola Scriptura.
Sola fide.
Sola gratia.
Solus Christus.
Soli Deo gloria.
These five statements are called (aptly enough) the "five solas", and are central to Protestant theology.
Sola Scriptura means "Scripture alone" -- that the Bible is the only inspired authoritative Word of God. (No apologies to Joseph Smith and those of the Mormon church).
Sola fide means "faith alone" -- that it is through faith that we are saved, not by any act or work of our own.
Sola gratia means "grace alone" -- that God has chosen to save His people not because of their merit but because of His unending grace.
Solus Christus means "Christ alone" -- that Jesus Christ is the only perfect Son of God and mediator on our behalf, who alone provides justification and redemption. I've touched on this before, but the summary version is that there is no way to salvation except in Jesus Christ.
Soli Deo gloria means "to God alone, glory" -- that the purpose of all creation - the reason anything exists - is that God alone be glorified. This one seems easy, but we so often lose track of it.
The latter four are pertient to the topic I'd like to discuss: the sufficiency of Christ's sacrifice, versus what I call the "Jesus Plus" mindset.
I call it the "Jesus Plus" mindset, because it can be boiled down to a simple statement of the form: "salvation requires confession and acceptance of the sufficiency and lordship of Jesus, plus...."
Of course, it's not often -- if ever -- stated so simply. And that's what makes it dangerous, because it can creep into our theology and our worldview unnoticed if we are not careful and discerning.
There are easy targets, of course; the most well-known is the Roman Catholic doctrine requiring both faith and good works for justification. Going back farther, the Pharisees were in a way all about this idea; that adherence to God's law plus their traditions made them right before God.
But there are also the ones that seem to creep into our minds couched in perhaps-correct ideas. Must one be baptised in order to be saved? Can a Christian be a Christian while not attending church?
Certainly baptism is good -- Christ commands us to make disciples of all the nations, baptising them in the name of the Father, Son and Holy Spirit. ([Matt. 28:18-20][3]). And a Christian ought to attend church when possible -- there are responsibilities that we have to fellow believers which a Christian cannot perform when separated from the assembly of believers.
But nowhere are we told that baptism or church attendance are required for salvation. Rather, we are told in Ephesians 2:
[Ephesians 2:1-9][4]
And you were dead in the trespasses and sins in which you once walked, following the course of this world, following the prince of the power of the air, the spirit that is now at work in the sons of disobedience --- among whom we all once lived in the passions of our flesh, carrying out the desires of the body and the mind, and were by nature children of wrath, like the rest of mankind.
But God, being rich in mercy, because of the great love with which he loved us, even when we were dead in our trespasses, made us alive together with Christ --- by grace you have been saved --- and raised us up with him and seated us with him in the heavenly places in Christ Jesus, so that in the coming ages he might show the immeasurable riches of his grace in kindness toward us in Christ Jesus.
For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast.
This is sola fide, sola gratia, solus Christus, and soli Deo gloria all bound together; by faith, not works, we are saved into the immeasurable grace of our God only through His Son Jesus, that He may be glorified in our redemption and our sanctification.
We should take caution in any doctrine or tradition to which we adhere (and not all tradition is bad!) that we do not place saving spiritual value in these things. Nothing can ever be permitted to supercede the preeminence of Christ and His work -- that work which is the pivotal moment of human history.
If, as I've said before, we attempt to somehow contribute to our salvation, we actually spite our all-sufficient perfect Savior. Contrasted to Christ, we can offer nothing. Without Christ, we are dead in our trespasses and sins, and thus entirely incapable of doing good. Any good that can come of us is not of us but rather of our Lord working through us, regenerating and renewing the corpses of our souls. All we have to offer is imperfection and the evils of our own hearts.
100% God plus 100% Man is not, as I've so often heard before, 100%. Though we cannot through our own flaws and arrogance somehow reduce God's perfection and magnitude, we do act in opposition to Him when we seek to rival His work with standards of our own.
Jesus Plus anything is less perfect that Jesus alone.
The result of this doctrinal equation in four constant solas is that while we must be cautious not to hold faith in anything but Christ for salvation, we can rest assured in His sufficiency, no longer praying that we will be "good enough" -- because we never will -- but rather trusting that God will be glorified in us.
For Christ alone always be glorified.
[3]: http://www.esvbible.org/Matthew 28:18-20 [4]: http://esvbible.org/Ephesians 2:1-9