“Being justified freely by his grace through the redemption that is in Christ Jesus”(Romans 3:24).
On October 31, 2017, we Bible believers celebrate the 500th anniversary of the beginning of the Protestant Reformation!
“Sola gratia,” another Bible teaching the Reformers recovered (not invented!), is Latin for “grace alone.” How can we be justified—made right—before God? By God’s goodness alone? Or, because of God’s goodness and our goodness?
As per “sola Scriptura”—by Scripture alone—we see that Adam has caused man’s nature to be corrupt from conception. After committing his horrible sin with Bathsheba, King David confessed in Psalm 51:5: “Behold, I was shapen in iniquity; and in sin did my mother conceive me.” When David prayed, verse 1 has him saying: “Have mercy upon me, O God, according to thy lovingkindness: according unto the multitude of thy tender mercies blot out my transgressions.” Why would God forgive David? Because of David’s “goodness?” Nay, evil David would be forgiven only because of God’s grace!
Jeremiah 17:9 says: “The heart is deceitful above all things, and desperately wicked: who can know it?” The Lord Jesus affirmed in Mark chapter 7: “ And he said, That which cometh out of the man, that defileth the man.  For from within, out of the heart of men, proceed evil thoughts, adulteries, fornications, murders,  Thefts, covetousness, wickedness, deceit, lasciviousness, an evil eye, blasphemy, pride, foolishness:  All these evil things come from within, and defile the man.” No wonder Romans 3:23 says: “For all have sinned, and come short of the glory of God;….”
Frankly, God does not “owe” us a way to Heaven, as there is nothing in our nature that He accepts. In fact, His justice demands that His righteousness be enforced. Anything short of His holiness—including man’s sin nature—deserves His wrath. That fury is Hell and, ultimately, everlasting punishment in the Lake of Fire. No religious activity (water baptism, church membership, confession, prayer, et cetera) can abolish man’s sin nature or rescue him from his deserved eternal doom. As David realized, man, spiritually bankrupt, must look beyond himself and his feeble abilities to God’s grace, what God can do for him! source