Мусар к Ийова 28:3

The attribute of Justice is not to be confused with עקא, distress, rather it means that man is to be treated according to his just deserts, be it reward or punishment. The only reason it is a source of distress to be judged by is the fact that we are all unable to measure up to its yardstick. It is thus quite normal that both Jacob and Esau were offspring of Isaac. One of them was destined for oblivion, the other for eternal life. Both are alluded to in the name קצחי. The קץ, "end," part of the name alludes to Esau, the סטרא אחרא to which the Zohar has linked it when commenting on קץ כל בשר בא לפני, "I have decided to put an end to all flesh" (Genesis 6,13). Samael is also referred to as קץ הימים, the end of all days, seeing he puts an end to our "days." The same word is also used to describe חשך, darkness. We read in Job 28,3: קץ שם לחשך, ולכל תכלית הוא חוקר, "He (G–d) sets bounds to darkness, to every limit man probes." Jacob, on the other hand, represents life, i.e. חי as in חי רב פעלים איש, (Samuel II 28,20). The Talmud Taanit 5 makes a point of telling us that יעקב אבינו לא מת, that our patriarch Jacob did not die. We derive all this information from the name קצחי.