What Is the Difference Between Justification and Sanctification?

They are merely different parts of the same process.

Justification is the remission of our sins and our entrance into the Christian life. We are initially justified at baptism and then each time we go to confession and finally in our final judgment.

Sanctification is the growth of grace and charity in a person. Once our sins our forgiven we must grow in holiness and will continue to do so throughout our lives until our final judgment.

They are subtle parts of the same process. For example, justification is your father giving you a car (righteousness/salvation) and sanctification is you and your father maintaining the car (cooperation with grace). You need to have a car to maintain a car, and you need to maintain a car to keep a car. The gift and the maintenance are intrinsically linked to each other in the ultimate goal of possessing the car.