Albert Barnes Commentary Exodus 18:13

"And it came to pass on the morrow, that Moses sat to judge the people: and the people stood about Moses from the morning unto the evening." — Exodus 18:13 (ASV)

From the morning unto the evening - It may be assumed as at least probable that numerous cases of difficulty arose out of the division of the spoil of the Amalekites (Exodus 17:13), and causes would have accumulated during the journey from Elim.