God encourages Moses by reassuring him of who He is and that He will lead His people out. Moses shares this with the Israelites, but they do not listen. Moses also doubts whether Pharaoh will listen.
Jacob’s son Levi had a son named Kohath, who in turn had a son named Amram. Amram fathered both Moses and Aaron.
7. I will take you to be my people, and I will be your God, and you shall know that I am the LORD your God, who has brought you out from under the burdens of the Egyptians.
The descent of Moses and Aaron from Levi, as described here, is unlikely to be comprehensive. It is more likely that Moses and Aaron were descendants of Amram, rather than direct offspring. It is common in Jewish genealogies to skip generations, similar to what is seen in the Gospels.
In verse 3, God makes an interesting statement, revealing that He was known to the patriarchs as El-Shaddai (God Almighty) rather than as Yahweh (The Lord). Here, God himself makes it clear that He is known differently to different people. This is important because it reduces the likelihood that the different appearances of God result from different authors with distinct theological agendas. Instead, it suggests that these differences stem from the various ways in which God chose to reveal Himself at different times.