Rashi (from Sanhedrin 38a): Hashem built the world with Chachmah. Sanhedrin 38a - man was created at the end, so he would find everything ready for him to eat. A parable explains this. A king built palaces and fixed them up. He prepared a banquet, then he brought the guests in.

Malbim: This returns to "Hashem Kanani Reishis Darko" (8:22) - the world was built via Chachmah. The building of the world is compared to a house. "B'Chachmah Yivneh Bayis" (24:3) discusses building the world - "Hashem b'Chachmah Yasad Aretz" (3:19). The verse depicts that immediately, on the first day of Ma'ase Bereishis, He built the house. In it was built the Bayis Kelali - from non-existence to existence. The Midrash compares this to one who sowed six seeds [at once; each sprouts in its time].

Rashi (from Sanhedrin 38a): These are the seven days of creation ¹ . Malbim - after building the Bayis Kelali on day one, the particular creations came into existence, each on in its day. They are the pillars of the world. The Bayis built via the first Dibur was in the air, suspended loosely on the Hiyuli; it was potential, but not actualized. In the seven days these pillars were actualized, and the Bayis was established solidly on them.

Rashi (from Shabbos 116a): This refers to the seven Seforim of the Torah, according to Rebbi. From the beginning of Bamidbar until "va'Yhi bi'Nso'a" is one Sefer, Parashas "va'Yhi bi'Nso'a" is a second, and the rest of Bamidbar is a third Sefer.)

Tosfos (38a): The world lacked rest; this was created on Shabbos.

Malbim: On Shabbos was created the primary pillar on which the Bayis stands - wondrous conduct and overriding nature.