Romans 5:10  “…if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life”
Because Christ lives, He can mold us into His image.  We aren’t just saved from sin, but transformed into what He intended us to be.

15  “…not as the offence, so also is the free gift…through the offence of one many be dead, much more the grace of God…abounded unto many”
Paul seems to set up a contrast between Adam’s sin affecting mankind and Christ’s gift of grace saving mankind.  But I’m not clear on the aspect of contrast.  Appears to show that one man affected all men and then another man affected all men.  Not much of a contrast of context.  Sounds more like a comparison than a contrast.  Certainly a contrast in intent and result.  Adam’s action resulted in death for all men while Christ’s resulted in life for all.  Perhaps that is the contrast intended.  “Many died” contrasted to “grace” which “abounded to many” which would bring life.

16  “…judgment was by one to condemnation…free gift is of many offences unto justification”
All sin came from the one sin that Adam committed, but the gift of Christ cleanses us from all sin, not just the one.

I hope you enjoy reading and studying His word.  May it accomplish what He desires.  Please feel free to comment or post questions.  Thanks for reading!