The term “elder” (Hebrew zaqen) first appears in Exodus 3:16 where the Lord tells Moses to go and gather together the elders of Israel to proclaim that God will deliver them from slavery.
16 Go and agather the elders of Israel together, and say to them, ‘The Lord God of your fathers, the God of Abraham, of Isaac, and of Jacob, appeared to me, saying, b“I have surely visited you and seen what is done to you in Egypt; 17 and I have said cI will bring you up out of the affliction of Egypt to the land of the Canaanites and the Hittites and the Amorites and the Perizzites and the Hivites and the Jebusites, to a land flowing with milk and honey.”
The word translated means those who are “old men” but the following “of Israel” adds the sense that these are men who have both age and reputation, a standing within the broader community, even the whole nation. The fact that the Lord continues to instruct Moses to take these elders with him into the presence of Pharaoh as a delegation representing the Hebrews reinforces this idea (Ex. 3:18). Moses then goes with Aaron to Egypt and to the Elders first to establish contact with the people (Ex. 4:29).
The role of these elders in the society of the Hebrews at this time is understood to be as leaders of clan groups, by which the whole nation was organised. This clan organisation may very well have been extant during the time of slavery. Certainly, elders are mentioned amongst the Egyptians in Genesis 50:7, and they first appear in Hebrew society 400 years alter in Moses time. But that is not to say that the Hebrews copied the Egyptian form of social organisation since most societies, (except perhaps our own in more recent years) has respected and revered the position, accumulated wisdom and dignity of the aged (Lev. 19:32).
So it was natural that all the directives and rules that God gave to Moses, he would then deliver to the people through the Elders. The best example of this is on the eve of the Passover, when having received instruction from the Lord on what to do, Moses then goes to the Elders and tells them in turn to instruct the families of their clans on how to observe the feast (Ex. 12:21). And the effect is that through their representative leaders, they observe the command of the Lord from Moses (Ex. 12:27-28).
The Elders are the ones whom God uses to support Moses authority before the people. The Lord gives Moses instructions to take with him some of the Elders