“Therefore.” The Greek conjunction dio (#1352 διό) means “therefore, wherefore, on account of.” At first, it seems confusing because a surface reading seems to be saying that because of the vices of the evil people who have been given over to shameful acts and evil behavior, “therefore,” everyone else is without excuse if they judge anyone. Hendriksen writes: “Many are puzzled by the word ‘Therefore.’ It must be admitted that the meaning is not immediately clear.”a Lenski is correct when he states that the “Therefore” connects, not just the closing verses with chapter 2, but the entire previous section, Rom. 1:18-32.b Also, Paul is not writing a blanket condemnation of judging. We must judge others, and judge on a daily basis, in order to obey the commands of God. Jesus said, “Do not judge by appearances, but judge with right judgment” (John 7:24). Paul warned us to “…watch out for those who cause divisions and put obstacles in your way that are contrary to the teaching you have learned. Keep away from them” (Rom. 16:17), and we cannot keep that command unless we make judgments about people. Paul also wrote many instructions to Timothy, including who to avoid and who to select for leadership based on behavior and qualifications, which is impossible to do without making a judgment about people. To fully understand the “therefore,” we must realize it refers back to the whole previous section of Romans, and points forward to those who judge but “practice the same things” (Rom. 2:1).
“O, you.” The Greek is “O man,” but the word “man” is generic here in the Greek text, and refers to both men and women. Different English versions have tried to make that clear in different ways. Some have almost omitted it altogether, but since the expression is emphatic that does not seem to be the correct way to handle it. The translation, “yes, you” seems to capture both the emphatic and inclusive meaning.
“in those things in which.” The point is not, in that you judge, which would simply deride the act of judging. The Greek is more specific. Paul speaks of in that which you judge—in other words, the very act that you judge, this act you are doing. Paul is not deriding being judgmental in this case, but hypocrisy.