52. Once, during Elul, Reb Yitzchak Dovid Gutfarb zt'l arrived at the beis din in Yerushalayim. The dayanim asked him, "Do you have a case today?" He replied that he didn't.
People were discussing the awesome judgment of Rosh Hashanah, and one person quipped, "We must believe that Hashem will give us a good judgment on Rosh Hashanah." The Brisker Rav told him that his calm attitude isn't bitachon. "Bitachon is only where there is fear. When one isn't afraid, there is no bitachon. That is not being aware of what is going on." Bitachon follows fear. We should be afraid on the days of awe, and then strengthen ourselves with bitachon, believing that Hashem will undoubtedly grant us a favorable judgment. In this manner, fear and joy merge. But if we aren't afraid at all, it could be that we are ignoring the reality of the occurring judgment.
The Tur (581) writes that most people wear black clothing when being tried in court and their lives are on the line. However, the Jewish nation wears white clothing because they trust that Hashem will perform a miracle and save them.
We wonder, why do we wear white clothing on Rosh Hashanah? Why don't we wear colorful clothing since we are sure that we will have a good judgment?
The Prishah answers that wearing colorful clothing might imply that we aren't afraid of judgment. Perhaps we don't know that we are being judged, which is why we are so calm and relaxed. By wearing white clothing, the clothes of tachrichim, we show that we know there's a judgment, only we rely on Hashem to give us a good judgment. It is a joy and calmness that emanates from fear, not from denial.