Rabbi Roodyn

י) אִמְרוּ בַגּוֹיִם ה’ מָלָךְ אַף תִּכּוֹן תֵּבֵל בַּל תִּמּוֹט יָדִין עַמִּים בְּמֵישָׁרִים:

Say among the nations, “Hashem has reigned.” Also the inhabited world will be established so that it will not falter; He will judge peoples with equity.

Even though society must be founded on tzedek, it is not enough that each individual should merely acknowledge justice by confining himself within the limits designated by law, not only with respect to his own claims, but also regarding the services that he may be expected to give to others.

An attitude that is based on the need to keep to the letter of the law will neither help man achieve perfection nor advance the salvation of all of human society. Chazal tell us (Bava metzia 30b) that Yerushalayim was destroyed because its inhabitants were content to act simply in accordance with the strict letter of the law.

Rav Hirsch therefore explains that when it comes to our interactions with others, tzedek alone is not enough. Rather we need to take into consideration the concept of tzedaka, the ‘duty’ that commands us to give to our neighbour something that he does not legally deserve, but that is necessary for both his welfare as an individual and for the fulfilment task which Hashem has given to all of us as a nation.

Here a life spent in fulfilling one’s duty to others by dealing kindly with them is called meisharim, it is a life lived in a fashion that is yashar, straight, and in accordance with our nature and destiny.