אגרת הקדש סימן ז’ 4
All Yidden must do all Mitzvos (and learn all of Torah) as תורה אחת ומצוה אחתצ לכולנא and still there is זהיר טפי in each time and Gilgul
these differences are called “חלק” each Yid’s portion in Yiddishkeit and cannot be explained logically, thus, it is also called גורל. אגרת בקדש סימן ז’ 4