The Jews' response? And they did not listen to Moses out of shortness of breath and from the hard labor.
A commentary explains that they weren't able to heed Moses' call - not only from physical breathlessness, but because they lacked the spirit. Having suffered in bondage for so long, they no longer had the faith or hope to believe that freedom was still in the realm of the possible. It was simply beyond them. They had lost the spirit and therefore, they could not hear, meaning they could not absorb, Moses' message.
It happens all too often. We may become so set in our simple ways that we give up hope of ever achieving a breakthrough. We simply lose our resolve.
There is a wise saying from of the legendary Chasid, Reb Mendel Futerfas. "If you lose your money, you've lost nothing. Money comes and money goes. If you lose your health, you've lost half. You are not the person you were before. But if you lose your resolve, you've lost it all."
Moses brought new hope to a depressed, dreamless nation. He gave them back the spirit they had lost and eventually, through the miracles of G-d, the promise was fulfilled and the dream became destiny.
To be out of breath is normal. To be out of spirit is something the Jewish People can never afford.
May we never lose the spirit!