29 And Moses and Aaron went and gathered together all the elders of the children of Israel: 30 And Aaron spake all the words which the Lord had spoken unto Moses, and did the signs in the sight of the people. 31 And the people believed: and when they heard that the Lord had visited the children of Israel, and that he had looked upon their affliction, then they bowed their heads and worshipped.
Aaron spoke, the signs were performed, and the people believed, just as the Lord had foretold. The Israelites were ready for deliverance, receiving the promise with reverence, not skepticism.
Years ago, Moses had already tried to help the Israelites and he had been rejected. But back then he had acted alone, according to his own wisdom and ability, whereas now he had come as an extension of the Lord. It can be hard to try to do something good, fail at it, and then accept that triumph can only come by giving it over to God. That requires great humility, and surrendering of self, and trusting in uncontrolled outcomes. This is very challenging and daunting to do, but for the most important things in life, it is the only way to succeed.
And as for Moses’s prior hesitancy, we never hear of it again. He resisted God’s plan leading up to this stage of the plan, but from this point on he remains a rock, constant and committed through every twist and turn.