Another interpretation of "Justice, justice you shall pursue" (Isaiah... Deuteronomy 16:20): it says "justice" two times. This is a warning to the judges who try capital cases, that they should not cut off the judgment on the same day, but rather they should let the judgment lodge overnight, in the manner that they let it lodge overnight in Jerusalem, as it is said, "[I was full of justice;] righteousness would lodge in her" (Isaiah 1:21).
Why Capital Judges Must Sleep on a Verdict Before Ruling
Midrash Tanchuma Buber, Shoftim 7:4
ד"א צדק צדק תרדוף שני פעמים, אזהרה לדיינין שדנין דיני נפשות, שלא יהו חותכין את הדין ביומו, אלא יהו מלינין את הדין, כדרך שמלינין בירושלים, שנאמר [מלאתי משפט] צדק ילין בה (ישעיה א כא).