What does Exodus 6:22 mean?

Following Izhar's descendants (Exodus 6:21), the text skips the descendants of Kohath's next son, Hebron (Exodus 6:18), and moves on to the descendants of his fourth son, Uzziel. He is elsewhere specified as an uncle of Aaron (Leviticus 10:4). It is important to note that five other men named Uzziel are mentioned in the Old Testament, including a Simeonite leader (1 Chronicles 4:39–43), Uzziel son of Bela (1 Chronicles 7:7), a son of Heman (1 Chronicles 25:4), a son of Jeduthan (2 Chronicles 29:14), and a son of Harhaiah (Nehemiah 3:8).

Uzziel's three sons included Mishael, Elzaphan, and Sithri. Mishael and Elzaphan are important in their work concerning the bodies of Nadab and Abihu (Leviticus 10:4). Another Mishael is noted in Nehemiah 8:4. The man most famously known as Meshach, from the story of the fiery furnace (Daniel 3), was originally named Mishael (Daniel 1:6–7). Sithri is not mentioned elsewhere in Scripture.