Granted, not all "Christians" may agree as many try to still earn their salvation.
For me, Christianity differs from all other religions because it is a relationship with God. We do good works because that relationship inspires and compels us to do so, because of the love of the one with whom we have a relationship.
We do not have the relationship because of good works that we do. We know in our hearts that the relationship is an unearned blessing given to us by God's grace and continues after the body 'gives up the ghost (spirit)' so to speak. That blessing is given to all who are willing to receive it on God's terms, not our own.
The relationship is the sum total of what Christianity is.
It is not a set of rules, regulations, rituals, dogma that is required to be followed. It isn't something we can earn. It just is.