The Purpose of Creation: Sanctifying the Mundane (Living al Kiddush Hashem)
This past Shabbos a cousin of mine was bar mitzvah. Here's the dvar Torah I delivered at Sha'alos Seudos - one you can use at a future Bereshit bar mitzvah (or possibly even other parshiyot since the ideas are of general application).
The first pasuk of the Torah, parshat Bereshit, reads "Bereshit bara Elokim et hashamayim v'et ha'aretz." Rashi immediately exclaims that this pasuk cries out for interpretation. He then explains that the word "Bereshit" stems from "Reshit" - the "beginning," and alludes to the Torah and the people of Israel both of which are also referred to as "Reshit" elsewhere in the Tanach (Mishlei 8:22 and Yirmiyahu 2:3).
Rav Sternbuch, in his parsha sefer Ta'am V'Da'at, cites a midrash stating that the world was also created for the sake of 3 mitzvot which are also referred to as "Reshit" - (1) bikkurim ("reshit bikkurei admatecha," Shemot 23:19); (2) chalah ("reshit arisoteichem chalah tarimu," Bamidbar 15:20), and (3) terumah/ma'aser ("Reshit degancha tiroshcha v'yitzharecha," Devarim 18:4).
Rav Sternbuch asks why are these 3 mitzvot singled out as being the purpose for which the world was created - after all, there are 610 other mitzvot that are important.