Romans 14:10

But thou, why dost thou judge thy brother? or again, why dost thou set at naught thy brother? for we shall all stand before the judgment seat of God.

The plaintive manner of Paul's question shows not merely disapproval, but wonder and incredulity that people could be so oblivious to their own need of mercy in the impending judgment, and so unreasonably conceited as to busy themselves with judging their fellow Christians. Thus, in this another instance, looms the large problem which is never very far out of sight in this entire epistle, namely, that of human pride and conceit. In fact, careful study of Romans shows quite clearly that practically all of it bears on this very thing. In the early chapters, the inclusion of all under sin, and the great emphasis throughout that salvation may not be deserved or earned by any, and the efforts in Romans 10-11 to remove the emerging conceit of the Gentiles, the blunt warning against it in Rom.12:16, and bearing on it throughout that entire chapter, as well as the outcropping of the problem here - all these things show how full was the apostolic awareness of this universal human trait and how thoroughly Paul strove to destroy it. As Greathouse observed:

We are responsible to Christ: we shall appear before him; there is therefore no place for uncharitable judgments or self-righteous exclusiveness between Christian men.[8]

The judgment seat of God ... What an antidote for conceit that is! This is the same as "the judgment seat of Christ" (2 Corinthians 5:10); and, again from Greathouse:

Notice how easily Paul passes from "Lord" to "God." The Father and the Son were so united in his mind that they were often interchanged. God, or Christ, or God through Christ will judge the world. Our life is in God, or in Christ, or with Christ in God. The union of man with God depends upon the intimate union of the Father and the Son.[9]

The direction of the thought here through the twelfth verse is: stop judging thy brother, for God will judge him AND YOU!

[8] William M. Greathouse, Beacon Bible Commentary (Kansas City, Missouri: Beacon Hill Press, 1968), p. 280.

[9] Ibid.