Exodus 18:26

And they judged the people at all seasons
Any day in the week, or any time in the day, whenever there was any occasion for them, and cases were brought before them:

the hard cases they brought unto Moses;
that is, the judges brought them to Moses when such came before them which were too hard for them, it was difficult to them to determine rightly about them, then they brought them to be heard and decided by him; for the judges, and not the people, best knew when a case was hard or easy to determine:

but every small matter they judged themselves;
and gave it as they saw was most agreeable to justice and equity, and did not trouble Moses with it; by which means he was eased of a great deal of business and fatigue, which was Jethro's view in giving the advice he did.