Romans 5: 12-21  Paul continued to lay out his thorough argument explaining the whole of the gospel of Jesus Christ.   He has made it clear that all of us are sinners, guilty and condemned, rightfully due the punishment of death .   He has shown us that God's wrath is just and impartial. And, he has clearly explained that it is only through faith in Jesus Christ that we can be saved from that wrath, for it is God's gift of grace to all who will believe.  God displayed His righteousness in the blood of His Son shed for us.. the propitiation, the atonement,  the payment of our penalty.  Because we have been justified - declared innocent through faith in Jesus, we are welcomed into the glory of God's presence.. reconciled with Him.

In these next verses, Paul gives us a contrast between Adam, through whom sin entered mankind, and Jesus, through Whom grace has come.

When Adam sinned in the garden "sin entered into the world and death through sin..."
Death "reigned"- it ruled; it was king .. . and it spread through all the world as all sinned.
Sin resulted in judgement which resulted in condemnation.
One man - one transgression - one act of disobedience - brought about condemnation for all.
The Law was given " that transgression might increase.."   - so sin would abound - superabound .
Sin was "imputed" reckoned and put on our account, when the Law was given.  The Law made it clear that sin abounded and brought death to every man. Sin abounded before the Law was given, but it superabounded when Truth was revealed through it and in spite of it.

In Christ Jesus grace abounds.   More than sin - which spread and increased to all of mankind - the grace of God - the free gift through the One - abounds more!  "... much more those who receive the abundance of grace and the gift of righteousness will reign in life through the One, Jesus Christ." 
One act " of righteousness" resulted in "justification of life to all men." 
Through the "obedience of the One, the many will be made righteous." 
Sin increased, but grace increased more.
Sin reigned in death.. but grace reigns through "righteousness to eternal life through Jesus Christ our Lord." 

Death vs Life
Sin vs Righteousness
Condemnation vs Grace

Sin entered the world by one man's disobedience and it took over.  It's king was death.  It grew and spread and brought condemnation to every single person.

But, GRACE entered through Jesus Christ.  Grace overpowered sin.  Death has lost its throne!  Life - eternal life through Christ now reigns without end! Sin can never reign again.. it can never overcome grace.. it can never abound more than grace can.

Father, help our minds to grasp the glory of these truths!  You are so wonderful and amazing and gracious!  We give You praise and honor and glory!!!  Thank You for salvation through Jesus Christ our Lord. Thank You that grace reigns in life through Jesus.  Holy Spirit, fill us with spiritual wisdom and understanding of these great truths and transform our minds by Your resurrection power that lives in us.  Amen and amen.