Sola gratia or grace alone is one of the five solae (only or alones) of the Protestant Reformation. The phrase “grace alone” has become so common among us that it is sometimes taken for granted. It is assumed that this important sola is understood. The doctrine of grace alone is essential to understand God’s redemptive plan for us all. God’s redemptive plan began before the foundation of the world—“For he chose us in him before the creation of the world to be holy and blameless in his sight. . . .” (Ephesians 1:4).
God’s redemptive plan was executed perfectly by His Son Jesus Christ who gave His life to redeem us. This redemption was not based upon any merit in us but was freely given to us by God’s grace. Romans 3:24 says, “and all are justified freely by his grace through the redemption that came by Christ Jesus.”
While we may be able to understand the doctrine of grace alone, it is much more difficult to live out. It is the “alone” part of grace alone that causes many to struggle. I may believe, for instance, that God has saved me by His grace, but there is that egotistic part of me that wants to believe that God needs my help. It is grace alone that saves from the wrath of God, we can add nothing. Martin Luther put it this way in his explanation of the Third Article of the Apostles Creed: “I believe that I cannot by my own reason or strength believe in Jesus Christ my Lord, or come to Him, except the Holy Spirit calls me through the Gospel.”
It is grace alone that gives us assurance of salvation. I have dealt with many parishioners who have struggled with whether or not they are truly born again. I have found that those who struggled with this issue tend to be those who have not understood grace alone. When asked why they are struggling with assurance of salvation, the answer often is, “I’m not sure that I’m good enough.” My response: “Of course you’re not.” That is the whole point of grace alone. We can never be good enough. God’s grace is sufficient. Our comfort, our confidence, is in God’s grace alone.
Dr. James Molstre
Sola Gratia – Salvation By Grace Alone… The fact is, the more a person seeks credit for himself by his own efforts, the deeper he goes into debt. Nothing can take away sin except the grace of God. In actual living, however, it is not so easy to persuade oneself that by grace alone, in opposition to every other means, we obtain the forgiveness of our sins and peace with God. 
Every teacher of work-righteousness is a trouble-maker. Has it never occurred to you that the pope, cardinals, bishops, monks, and that the whole synagogue of Satan are trouble-makers? The truth is, they are worse than false apostles. The false apostles taughtthat in addition to faith in Christ the works of the Law of God were necessary unto salvation. But the papists omit faith altogether and teach self-devised traditions and works that are not commanded of God, indeed are contrary to the Word of God, and for these traditions they demand preferred attention and obedience. 
Now the true Gospel has it that we are justified by faith alone, without the deeds of the Law. The false gospel has it that we are justified by faith, but not without the deeds of the Law. The false apostles preached a conditional gospel. So do the papists. They admit that faith is the foundation of salvation. But they add the conditional clause that faith can save only when it is furnished with good works. This is wrong. 
The ‘Reformed Reader’ also points out “some great words from Luther on salvation by grace alone” “found in volume 3 of Baker’s 7-volume set of Luther’s sermons (edited by J. N. Lenker and others)”. They can also be read on pages 147-148 and 151 of Luther’s Christmas Sermons available on Amazon (Publisher: CreateSpace Independent Publishing Platform).
So he (Paul after conversion) discards all boasted free will, all human virtue, righteousness, and good works. He concludes that they are all nothing and are wholly perverted, however brilliant and worthy they may appear, and teaches that we must be saved solely by the grace of God, which is effective for all believers who desire it from a correct conception of their own ruin and nothingness.”
Yes, dear friend, you must first possess heaven and salvation before you can do good works. Works never merit heaven; heaven is conferred purely of grace.
He who does not receive salvation purely through grace, independently of all good works, certainly will never secure it.
Martin Luther quotes