Q. (Re- questions 2976,79). Why is it so important to be part of the first ten who make up the minyan?
A. Talmud (Brochos 47b) teaches that Rabi Yehoshua ben Levi said: One should always rise early to go to the synagogue in order to have the privilege and be counted among the first ten to complete the minyan, as even if one hundred people arrive after him, he receives a reward equivalent to the reward of them all. Rabenu Yonah and Maharsho (ibid.) explain that this is due to having caused the Shechina to be present in that place. (See similar in Zohar p. Nasso, regarding the presence of the Ten Sefiros).
Shulchan Aruch and Mishna Berura (90: 14) rule that this is a requirement to be fulfilled when possible.
It is also one of the few prime mitzvos that their fruits are offered in this world, while their principal is maintained and rewarded in the world to come.
Ateres Z’kenim writes that some Tzadikim would fast on the day that they were not able to be from the first ten. Medresh Rabbo (Bamidbor 21) mentions that Yehoshua bin Nun merited his position, because he always was the first to come and set the Beis Midrash.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a