Parshat האזינו is always read before the holiday of Succot. It is a good transition between Yom Kippur and the coming holiday. האזינו is also referred to as the שירה, as it is written in the form of a song.
It is a promise of the future גאולה. It was meant to give comfort and a reminder of all the blessings that would be seen in the future.
Idol worship will be totally eradicated, and the nations of the world will come to acknowledge the G-d of Israel. The שירה reflects all that we were praying for on Yom Kippur. Hashem will one day rule the world.
We are commanded to call out to Hashem and give glory to Him. From the words, הבו גודל לאלוקינו, the Talmud in ברכות says that this is the source for זימון, Benching with a quorum of three.
It’s as if the leader tells his two eating partners, “Now that we have completed our meal, let us give glory to G-d.”
We should leave Yom Kippur invigorated with a deeper love of Hashem, and enter Succot with confidence that great things are ahead. This is the message of שירת האזינו.