Adam Clarke on Exodus 3:16

Elders of Israel - Though it is not likely the Hebrews were permitted to have any regular government at this time, yet there can be no doubt of their having such a government in the time of Joseph, and for some considerable time after; the elders of each tribe forming a kind of court of magistrates, by which all actions were tried, and legal decisions made, in the Israelitish community.

I have surely visited you - An exact fulfillment of the prediction of Joseph, Gen 50:24, God will surely visit you, and in the same words too.