In Romans chapter 14, Paul uses the analogy of one person judging another’s slave, according to their own standards, in order to show the absurdity of one person judging another Christian—mind you, this only works with believers and not unbelievers, who are not slaves of God. The absurdity comes in at the idea that says that the one judging knows the end of the slave’s task or works. He does not.
One very large and important inference we can draw from this argument of Paul’s is that one cannot tell whether a slave of Christ is where he should be, because that slave of Christ has one very specific and predetermined goal: to glorify God; one certain end: to be sanctified. In order to judge, then, this servant of the Most High, we would need to know the order in which this life of sanctification is taking place and the means that God is using for this end.
To exemplify this point we can look at one other analogy. Consider a particular historical figure who had his own personal secret means to another certain predetermined end. Consider Michelangelo di Lodovico Buonarroti Simoni (a.k.a. Michelangelo) the sculptor—the artist. When Michelangelo was commissioned to create a certain work, the one paying the artist would often have a very good, if not total, idea of what the end would look like. However, if the commissioner came to the sculptor prior to the works completion and at various times, would he be justified in judging the work or not? Would he be right in telling Michelangelo that his partially carved piece of stone was not where it should be? No. He has no idea of where it should be. Even another artist would be unjust in making a premature judgment of a piece of art. How much more, then, should we not judge another Master’s work of art—a work of holiness?