Speak to Aaron and say to him: When you light (Beha'alotcha) the lamps (Num. 8:2)
As Rashi notes, from the word "Beha'alotcha," which means "going up," our Sages derived that there was a step in-front of the menora upon which the priest stood. A question is asked: If the menora was only three cubits tall, and therefore within easy hands-reach, why was it necessary for the priest to stand on something? The answer is that Aaron wore the special headdress of the High Priest, with its golden plate on which the words "Holiness to the L-rd" was engraved. As Jewish law forbids the High Priest from raising his hands higher than the gold plate, a step was placed in front of the menora to make his service more comfortable. (M'lo HaOmer)
And Aaron did so (Num. 8:3)
As the Midrash explains, "This comes to declare the praise of Aaron, that he did not act differently" (i.e., that he carried out everything G-d commanded him to do in an exact manner." Another person in the same situation might have lost his composure: spilled the oil, dropped the wicks, etc. Aaron, however, did not allow his intense emotion to interfere with the performance of his holy service. (Kedushat Levi)
Sing and rejoice, O daughter of Zion; for behold I come, and I will dwell in your midst, says the L-rd (from the haftorah, Zech. 2:14)
Our Sages taught that the Divine Presence only rests upon someone who is joyful. G-d therefore advises the Jewish people to rejoice, as preparation for His presence among them. (Tzavarei Shalal)
For behold, I will bring My servant Tzemach (literally "Branch") (from the haftorah, Zech. 3:8)
Why is Moshiach referred to by this name? To emphasize that even though it may seem as if the branches of the royal House of David have been cut off, the "root" still exists, and when the proper time arrives, Moshiach, a descendent of King David, will be revealed. In the same way that a root can lie dormant and concealed for many years, yet germinate and develop into an entire tree under the right conditions, so too will Moshiach arise to redeem the Jewish people when G-d determines the right time has come. (Malbim)