Sforno on Exodus 18:16/ספורנו על שמות י״ח:ט״ז

1כי יהיה להם דבר, when someone among these people who hold positions of public trust has a disagreement with one of his colleagues he brings it to me,

2בא אלי ושפטתי בין איש ובין רעהו, between these leaders of the community who come to me about matters of public concern.

3והודעתי את חקי האלוקים ואת תורותיו, to these highly placed individuals who approach me with the concerns of the public. We encounter similar occurrences described in slightly different words, such as in Exodus 34,31-32 “Moses called to them and Aaron and all the chieftains in the assembly returned to him, and Moses spoke to them.” Our sages in Eyruvin 54 describe the hierarchy of transmitting G’d’s word to the people. Moses learned the Torah directly from G’d; when Aaron entered his tent he told him what he had learned. Aaron would move over and take his seat on Moses’ left. After that Aaron’s sons would enter and Moses would instruct them in what G’d had taught him. This continued until Moses had taught the same lesson no fewer than 4 times. We can see that all this took time, and as a result the ordinary people had to stand in line for a long time.