And the L-rd spoke to Moses in the wilderness of Sinai, in the Tent of Meeting (Num. 1:1)
"In the wilderness of Sinai" teaches that a Jew should be as humble as Mount Sinai, the smallest of all the mountains; "in the Tent of Meeting" teaches that he should be joyous, as the word for "Meeting," "Moed," also means festival. The greater one's humility, the more genuine joy he will experience at having merited to be able to serve G-d. (Rabbi Elimelech of Lizhensk)
Take a census (literally "lift the head") of all the congregation of the people of Israel (Num. 1:1-2)
Moses' counting of the Jews caused the Divine Presence to rest among them. Every Jew realized that he was part of an exact, specific number, and that he, the individual, had the power to influence the fate of the entire nation. Similarly, Maimonides writes (in his Laws of Repentance): "Every person should consider himself...half innocent and half guilty, and the whole world as if half meritorious and half culpable. If he does one mitzva, he tips the balance to the side of merit and brings salvation and relief both to himself and entire world." Thus, by arousing them to repentance, the census caused G-d's Presence to dwell among the Jewish people. (Shnei Luchot HaBrit)