Comparison is a deadly thing when it comes to discipline. We are each will be rewarded based on the good we are called to do, regardless of our position. If I am a slave and I compare my good deeds to the deeds of someone who is free, I may begin to discount the good that I do. Likewise if I am free and compare my deeds to that of a slave, I may hold myself in higher regard than I should.
Likewise, as a Christian it is easy to get in the comparison trap. We look at the actions of other believers and think we are not doing enough. Or we looks at the actions of sinners and think we are more righteous than we are. The only thing that we can compare ourselves to is the good we do in obedience to the direction of Christ. We need to discipline our self to stop looking at others and start listening and looking to Christ for direction.
Our good deeds must be directed by Christ. All the good deeds in the world will not be rewarded if we are not doing what we are called to do. We are rewarded for the good deeds we do in obedience. We will not be rewarded for good deeds we do out of wrong motive or wrong attitude. We must discipline our self to be obedient to God. We must discipline our self to check our motives regularly. We must discipline our self to watch our attitude also.