Adorning Hashem
One of the verses in אז ישיר, is זה א-לי ואנוהו, this is my G-d and I will glorify Him. There are two interpretations to this Pasuk. The first comes from מסכת שבת that tells us that we are to adorn Hashem with Mitzvot in a beautiful way. We are to purchase a nice Lulav, ציצית, and ספר תורה. By showing we are not afraid to spend money on Mitzvot, we give adornment to Hashem.
The second explanation of ואנוהו, comes from Rabbi Soloveitchik and he says the word means אני והא, me and Him. It is meant to reflect on the special bond each one has with Hashem, and it is our duty to try to emulate Him. Just as He is kind and merciful, so must we. An interesting commentary on ואנוהו, from two perspectives.