What is the significance of "ha'Menorah ha'Tehorah"?
Rashi #1: It indicates that the Menorah was made of pure gold.
Rashi #2: It teaches that the Kohen had to place the oil for lighting on Tiharah Shel Menorah (the Menorah itself), and not on the ashes - which had therefore to be removed first.
Ramban (on Pasuk 2, citing the Toras Kohanim): It teaches us that the lamp-holders needed to be placed on Tiharah Shel Menorah (the Menorah itself), and not supported with small pieces of wood or stones. 1
Ramban 'Al Taharah shel Menorah'.
What are the ramifications of the words "Lifnei Hashem"?
Ramban: It indicates that Aharon should arrange the Neiros in their correct location in the Heichal, and not arrange them outside and bring the Menorah in afterwards.