In the opening of the story of the Jews in Egypt, we are told of two courageous women, Shifrah and Pu'ah, and their heroic efforts to save the lives of Jewish infants in defiance of Paroh's decree. Although they had received no direct instructions to disobey Paroh's order, they sensed moral outrage at its cruelty and acted unhesitatingly, despite the great personal risk involved. As a result of their unhesitating response, their reward from Hashem is immediate - ויעש להם בתים, Hashem gave them great families of their own (שמות א:כ"א).
As the Parsha unfolds, we are introduced to the hero, Moshe, who owes his very existence to Shifrah and Pu'ah. Moshe demonstrates concern for his fellow Jews, helpless Midianite shepherdesses, and his father-in-law's sheep - but when presented with an opportunity to rescue his people, he resists. "Who am I," he proclaims, "that I should go to Paroh and take the Jews out of Egypt?" (שמות ג: י"א). Hashem persists, but so does Moshe. "What could I possibly say to the Jews or to Paroh that they should listen to me?" (שם פסוק י"ג). Hashem's patience continues, but so does Moshe's resistance. "But they won't listen to me," he complains (שם ד:א'). Five times Moshe stalls and looks for excuses to avoid the mission, until Hashem's patience finally wears thin - ויחר אף ה' במשה (שם פסוק י"ד).
HaRav Joseph B.Soloveitchik, elaborating on the comments of Rashi on this Posuk, once explained that had Moshe not hesitated to accept this critical mission, he would have taken on the positions of both Kohein and Navi. In response to Moshe's self-deprecating modesty, claiming his unsuitability for the mission, Hashem took away the Kehunah and gave it to his brother Aharon. In fact, this very same Posuk in which Hashem's anger is expressed is the one in which Moshe is informed that his brother Aharon will meet him and become his spokesman. Moshe, who owes his very life to those who did not hesitate, hesitates himself and loses a once in a lifetime opportunity.
Moshe's hesitation apparently did not end with that conversation. After Hashem informs Moshe of his new partnership with Aharon, Moshe returns to his father-in-law and informs him of his impending departure, yet does not immediately leave. Hashem once again must come and tell him that it is time to go. "The time is right," says Hashem, "כי מתו כל האנשים המבקשים את נפשך" - for all those who seek to kill you have died (שם פסוק י"ט). Moshe finally leaves for Egypt, and stops along the way to spend the night at an inn. Mysteriously, Hashem comes to Moshe that night and seeks to kill him - ויבקש המיתו (שם פסוק כ"ד)! The same exact language used to convince Moshe that it was safe to return to Egypt is used to describe what Hashem wanted to do to Moshe. Did Hashem send Moshe to Egypt just so that He could kill him on the way?
Apparently, even after Moshe reluctantly agreed to take on the mission, he stalled for time, fearing for his safety. When Hashem told him that it was safe to go, Moshe went, only to face a new threat of death from Hashem Himself. Moshe hesitated going to Egypt lest he be killed by his enemies; Hashem was telling him that it wasn't those in Egypt he had to fear, but Hashem Himself. There was no way that Moshe could tell Paroh to immediately release the Jewish people in response to Hashem's command if Moshe himself hesitated before fulfilling his own Divine mission.
Interestingly enough, Tzipporah understood the importance of acting decisively. Without hesitation, she picked up a sharp rock and circumcised her son. That Bris Milah was a reminder of the Bris Bein Habesarim, in which Hashem promised Avraham that when the time was right, He would redeem His people from Egypt. The time was right, and Tzipporah acted decisively to invoke that Bris, "reminding" Hashem that Moshe was the one chosen to be the vehicle of that redemption. Then, and only then, was Moshe spared death.
When there is a mission of importance critical to the survival of the nation, the personal concerns of the individual are suspended. We have more to fear of Hashem's response to our inaction than of man's threats of retaliation to our action. Shifrah and Pu'ah understood this. So did Tzipporah. Moshe had to be taught.
It would seem that Moshe eventually understood the message. Later on, (שם י:כ"ח), Moshe's life is once again threatened, this time by Paroh himself. Here, Moshe stands tall and faces Paroh, delivering the final message of the death of the first born. In the face of evil, corruption, or immorality, we must seize the moment and confront it, following the examples of Shifrah, Pu'ah, Tzipporah, and eventually, Moshe.