Alone means “to the exclusion of all others or all else.”  If a billionaire revealed to you the secret location of a vault holding millions of dollars and gave you a key saying, “This key alone will unlock your fortune,” you would not want to lose that one irreplaceable key. Oops equals no fortune. At the same time, if the billionaire gave you one of 50 keys and forewarned you that the other 49 went to other people, you may want to snap to it to ensure you get at least some of the fortune. Alone makes all the difference.
Alone is a very important word for Protestants. Alone was a fundamental conviction of the Protestant Reformation and made all the difference in the minds of the Reformers. Though the Reformers didn’t word it exactly like this, these five alones or solas permeated their theology, piety, and practice : Scripture alone, Christ alone, grace alone, faith alone, and God’s glory alone. The essence of each alone played a critical role in reforming and purifying the church, indeed returning the true church to God-honoring theology, piety, and practice.
Scripture alone says that God’s inspired, infallible, and inerrant Word and self-revelation is the ultimate and final authority and rule on matters of faith and life, indeed it is the only rule to guide us in glorifying and enjoying God.  To say that anything else including church tradition, church councils, church creeds, and the like possess equal authority is to entirely destroy the ultimate authority of God’s Word and therein destroy the gospel of God’s free and unmerited grace in Christ. 2 Timothy 3:16–17 says:
All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness, that the man of God may be complete, equipped for every good work.
Alone makes all the difference.
Christ alone says that a sinner’s salvation depends entirely upon the righteousness and redemptive works of Christ Jesus the Lord done for the sinner, that indeed Christ Jesus is a sufficient and effective Savior, that indeed Christ is the only way to the Father. To say that Christ is Savior and that something else is also necessary for salvation is to entirely destroy the gospel of God’s free and unmerited grace in Christ. Acts 4:12 says, “And there is salvation in no one else, for there is no other name under heaven given among men by which we must be saved.” Alone makes all the difference.
Grace alone says that a sinner’s salvation is entirely a work of God’s sovereign grace for the sinner and freely given to the sinner as a gift and that the sinner’s moral works or merit play no role in his salvation at all. To say that salvation is by grace and by works is to entirely destroy the gospel of God’s free and unmerited grace in Christ. Ephesians 2:5, 8, and 9 says, “by grace you have been saved . . . this is not your own doing; it is the gift of God, not a result of works, so that no one may boast.” Alone makes all the difference.
Faith alone says that a sinner’s justification before God is the righteousness of Christ imputed or credited to the sinner through the sole instrument of faith and that moral works play absolutely no role in a sinner’s justification. To say that salvation is by faith and by works, by receiving and by earning, is to entirely destroy the gospel of God’s free and unmerited grace in Christ. Romans 3:28 says, “For we hold that one is justified by faith apart from works of the law.” Alone makes all the difference.
God’s glory alone says that all honor, worship, credit, praise, admiration, and esteem be given to the triune God of Scripture and not to anything else because God graciously achieved salvation for unworthy sinners. To give any glory at all to anything other than God is the most flagrant and horrific idolatry and is to cheat God of the glory due His great name. 1 Corinthians 10:31 says, “So, whether you eat or drink, or whatever you do, do all to the glory of God.” Alone makes all the difference.
Do you remember why the angel told Joseph to name the infant Jesus? It was because “he will save his people from their sins” (Matt. 1:21). There was no question whether Jesus would save his people. He would. None whom Jesus intended to save would perish (Jn. 17). This is one reason why I find Arminianism indefensible. Jesus is not a potential Savior who made salvation possible but not certain; Jesus is an actual and successful Savior in that he saves everyone God intended Him to save. The angel communicated certainty, “he will save his people from their sins.” To make the source of salvation Jesus and something else is to entirely destroy the gospel of God’s free and unmerited grace in Christ. Alone makes all the difference.
We come to Lord’s Day 11 and Heidelberg 29-30. Heidelberg 29 asks, “Why is the Son of God called ‘Jesus,’ that is, ‘Savior’? Listen for alone in the answer: “Because He saves us from all our sins, and because salvation is not to be sought or found in anyone else.” Don’t look to yourself. Don’t look to dead saints. Don’t look to Muhammed, Buddha, Joseph Smith, or even Moses and the Old Covenant. To look for salvation from all your sins in anything other than Jesus is an exercise in futility that leads to insecurity, anxiety, fear, delusion, and ruin. Jesus must stand alone as your Savior or you will not have salvation or abiding comfort and peace.
Let’s say your friend confesses Jesus Christ as their Savior and Lord, but then they also consider their own moral achievements a contribution to their salvation. Or maybe as they depend on Jesus they also depend on the treasury of merit which according to Roman Catholicism is the merits of Christ and the merits of saints available to believers. Does your friend actually believe in Christ? Do they actually trust Christ? No. They trust Christ and something else which means they don’t trust Christ because they don’t trust Christ alone. Alone makes all the difference. Heidelberg 30 says:
Do those believe in the only Savior Jesus who seek their salvation and well-being from saints, in themselves, or anywhere else? No. Though they boast of Him in words, they in fact deny the only Savior Jesus. For one of two things must be true: either Jesus is not a complete Savior or those who by true faith accept this Savior must find in Him all that is necessary for their salvation.
This is really important to understand. Many people who confess Christ believe a false gospel and actually deny Christ because they attribute their salvation to Jesus plus something else, whether that would be their own supplemental moral achievements, the supplemental merits of dead saints, or anything other than Jesus. To add something to Jesus is to deny Jesus. If Jesus is 99.99 percent sufficient for salvation, and something else contributes 0.01 percent, Jesus would be an incomplete or partial Savior and therefore no Savior at all. A belief that Jesus is 99.99 percent is called unbelief. The only other option is true faith which receives Christ as a complete and sufficient Savior who has himself done all that is necessary for salvation, and in this true faith comfort and assurance are enjoyed.
Where is your true comfort found? Not in Jesus plus something else. Your comfort is found in knowing you are not your own, but belong with body and soul, both in life and in death, to your faithful Savior Jesus Christ who by himself paid for all your sins. You didn’t help him and neither did anyone or anything else. Jesus alone is your justification before God. Jesus alone is your salvation. Jesus alone is your comfort. Alone makes all the difference.
 Thank you Dr. R. Scott Clark for this phrase.
 The Confessions of Our Faith, Fortress Edition, ed. Rev. Brian W. Kinney (Fortress Book Service & Publishers, 2007), 124.
Quotes from the Heidelberg Catechism are taken from Zacharias Ursinus & Jonathan Shirk, The Heidelberg Catechism (Manheim: Small Town Theologian, 2021). Scripture quotations are from the ESV® Bible (The Holy Bible, English Standard Version®), copyright © 2001 by Crossway, a publishing ministry of Good News Publishers. Used by permission. All rights reserved. May not copy or download more than 500 consecutive verses of the ESV Bible or more than one half of any book of the ESV Bible.