Such words would have weighed heavily upon Moses, especially since he had been reluctant to embrace the role of deliverer to begin with. Lesser men would have left Egypt and never returned--but not Moses! He doesn't give up or despair but rather wisely brings his problems to God. "Lord, why have you brought trouble on this people? Why is it You have sent me? For since I came to Pharaoh to speak in Your name, he has done evil to this people; neither have You delivered Your people at all" (5:22,23). Moses does not yet understand but wants to, and God will explain it to him (or at least enough for him to better grasp "the big picture").
"Then the LORD said to Moses, 'Now you shall see what I will do to Pharaoh. For with a strong hand he will let them go, and with a strong hand he will drive them out of his land'" (6:1). It would happen as God described, though it would take some time (cf. John 13:7). Everything was on schedule and was foreseen by the LORD. He knew that their suffering must increase before they would be willing to leave Egypt (their frequent murmurings in the future and desire to return to Egypt prove this point). Moses, as deliverer, needed to be confident in the divine plan so God went on and spoke more words of comfort and explanation to him:
"I am the LORD. I appeared to Abraham, to Isaac, and to Jacob, as God Almighty, but by My name LORD I was not known to them. I have also established My covenant with them, to give them the land of Canaan, the land of their pilgrimage, in which they were strangers. And I have also heard the groaning of the children of Israel whom the Egyptians keep in bondage, and I have remembered My covenant. Therefore say to the children of Israel: 'I am the LORD; I will bring you out from their bondage, and I will redeem you with an outstretched arm and with great judgments. I will take you as My people, and I will be your God. Then you shall know that I am the LORD your God who brings you out from under the burdens of the Egyptians. And I will bring you into the land which I swore to give to Abraham, Isaac, and Jacob; and I will give it to you as a heritage; I am the LORD" (6:2-8).
The name "LORD" (i.e., YHWH or Jehovah, traditionally) was a new revelation in Moses' day. The patriarchs of old knew God Almighty, but not in the same sense that Moses and the Israelites would know Him (or "experience" Him). Moses and Israel were privileged to know God more fully because they experienced God's faithfulness to the promise He had made to the patriarchs. They would come to comprehend the greatness of God more fully than the patriarchs because of the powerful deeds God would perform among them and for them. Truth be told, we are even more blessed than those in Moses' day (cf. Heb. 8) for we can know God today even more fully through His fully-complete, inspired word.
Moses took the encouraging words from God and spoke them to the people, "but they did not heed Moses, because of anguish of spirit and cruel bondage" (Exo. 6:9). The sting of bondage is much more real to the Israelites at this point than is the hope of freedom and the promised reception of Canaan.
Moses is then instructed by God to go speak to Pharaoh again. Moses' confidence is clearly shaken. He replied - "The children of Israel have not heeded me. How then shall Pharaoh heed me, for I am of uncircumcised lips?" (6:12). Moses, with Aaron as his spokesman, would go back to Pharaoh. This narrative is recorded in Exodus 7, after some matters of genealogy and chronology are addressed.