God instructs Moses to gather the elders of the Israelites and announce to them that their ancestral God has appeared to him and given him the mission to free them from slavery and return them to their ancestral homeland. Additionally, God tells Moses that the elders will believe him (Exodus 3:18). Together, they will go to Pharaoh and demand their release. But Moses is skeptical. He fully expects that the people will judge him an impostor, doubting that he actually received a divine message (Exodus 4:1). The elders may believe him (See Sarna, New JPS Commentary on Exodus, p. 20), but the folk will not. To address Moses’ objection, God provides Moses with a series of signs to convince the people of Moses’ legitimacy. Those signs successfully convince the doubters among the Israelites (Exodus 4:30-31).
Oddly, Rabbi Hezekiah ben Manoah, a venerable exegete of the thirteenth century, writes that the three signs (staff turns into snake and reverts to staff, sudden onset leprosy and healing, and water turns into blood) were intended to convince doubting Egyptians! So, for example, regarding the third sign, Hizquni, the name by which his commentary is known, explains: “This water, once it had turned into blood on the ground, would not revert to become water again even when the plague had ended. This would serve as proof to the Egyptians that this phenomenon had its origin in heaven.” The text, however, clearly assigns the purpose of the signs to convince the Israelites. A commentator of the stature of Hizquni undoubtedly knows this, so it would be a stretch to ascribe it to an oversight.
Perhaps what Hizquni wants to convey is that skepticism is not restricted to the Israelites alone. Whether Egyptian or Israelite, the fact is that someone who purports to speak in the name of a supreme power and makes demands on others should be ready with some evidence to support the claim. The Israelites, dispirited by four hundred years of slavery, would be hard pressed to believe that their status could change. The Egyptians, the mightiest earthly power of the time, would be hard pressed to believe that some invisible entity could dictate any change in their society. Moses implicitly understood what George Carlin articulated:“Tell people there’s an invisible man in the sky who created the universe, and the vast majority will believe you. Tell them the paint is wet, and they have to touch it to be sure.”
With a set of signs like arrows in his quiver, Moses was now equipped to better address his skeptics.