Haazinu means "Listen." Moshe asks heaven and earth to be witnesses, saying, "Listen, O heavens... and hear, O earth.""
Many generations later, the prophet Isaiah also called upon heaven and earth to bear witness. Isaiah says, "Let heaven hear, and let earth listen.""
What is the difference between the words of Moshe and those of Ishaiahu?
Moses calls the heavens to listen and the earth to hear, while Isaiah calls the earth to listen and the heavens to hear. To listen means that the people communicating are close. To hear applies when they are far away. Our sages explain that Moses was on a very high level, closer to heaven than to earth. So, when he spoke to the heavens, he said, "Listen," and to the earth, he said, "I heard.".
Ishaiahu was on a lower level. He spoke to the heavens from below and said "I heard," while to the earth he said "listen.".
The parashah Haazinu is always read on the Shabbat before or after Yom Kippur. At this time, we can "seek God when He is near, call upon Him when He is near." During these days, every Jew is like Moses, close to God. This assures us that He will hear our prayers and grant us a year filled with blessings and happiness.
Extracted from please tell me what the Rebbe says.