Moshe Rabbeinu was given three signs to utilize in order to convince B'nei Yisroel that Hashem was initiating the process of their redemption:

1. Moshe's staff became a snake and then reverted to being a staff once Moshe grasped it.

2. Moshe's hand became afflicted with Tzora'as when he removed it from his chest, and when he returned his hand thereto, it was healed.

3. Moshe was told to take some water from the Nile and pour it onto the ground, and the water would become blood.

What do these three signs symbolize? Why did these specific signs resonate with B'nei Yisroel?

B'nei Yisroel were not merely physically enslaved; their minds were also enslaved, and they could not fathom the idea of freedom, largely due to the iron grasp that Pharaoh and the Egyptians had on their bodies and their lives. Escape from Mitzrayim seemed impossible and was unheard of. (V. Rashi on Shemos 18:9, from Mechilta.)

The three signs given to Moshe were tailored to address the fears and insecurities of B'nei Yisroel, enslaved and full of despair.

Moshe's staff, which became a snake, represented Pharaoh, who was likened to a serpent. (V. Yechezkel 29:3) This sign indicated that the serpent, Pharaoh, would be supernaturally subdued and rendered powerless to further subjugate and enslave the Jews.

Moshe's hand represented B'nei Yisroel. The hand was healthy, then quickly became afflicted with Tzora'as, and subsequently was totally healed in an instant. B'nei Yisroel likewise were a free, unfettered, thriving nation, which quickly became enslaved (as soon as Yaakov's sons had all died - v. Rashi from Medrash on 6:16). The instant healing of Moshe's hand and its restoration to health signified that B'nei Yisroel likewise would undergo a rapid healing via restoration and redemption to their former, glorious and free state. The previously free nation, which became afflicted with slavery, could and surely would again be suddenly freed, despite the seeming impossibility.

The water which became blood symbolized the Egyptians, whose survival depended on the Nile. (V. Rashi on Bereshis 47:10, from Medrash Yashan.) The same Egyptians, who with ruthless confidence exploited B'nei Yisroel as a national resource, reliant upon free Jewish slave labor in the same way that they relied upon the Nile for national prosperity and livelihood, would be cursed and plagued like the Nile's water which turned into blood, and no longer be in a position to forcibly retain B'nei Yisroel as captives.

When Moshe presented these signs to B'nei Yisroel, he was in fact presenting supernatural messages that communicated statements of Hashem's ability to reverse the state of affliction and to redeem. These messages indicated that that which seemed impossible would occur, and that despair would evolve into hope and instant liberation. The captivating messages painted a detailed picture that immediately convinced B'nei Yisroel that the Ge'ulah (Redemption) was approaching, for just as Moshe perceived God speaking to him from the flame in the bush, so too did the Jews perceive God and know His truth from the unique signs presented by Moshe.