John Calvin Commentary Exodus 18:24

"So Moses hearkened to the voice of his father-in-law, and did all that he had said." — Exodus 18:24 (ASV)

So Moses listened. Here is a remarkable instance of modesty: Moses was not unwilling to submit himself to the counsel of his father-in-law. For although Jethro was his superior in age and in degree of affinity, in other respects he was far inferior to him.

This yielding of Moses to his authority, then, lays down a rule for all the greatest and most excellent teachers, that they should not refuse to receive the admonitions of those whom they recognize as teaching rightly, even if they are not of such high standing. For Cyprian²⁰² truly declares that no one is a good teacher who is not also teachable.

It is probable that the old man immediately returned home, not out of contempt or from a dislike of labor or fatigue, but²⁰³ on account of his age; but we will later see in its proper place that his son remained in the camp.

²⁰² “Et ideo vir sanctus Cyprianus, (Ep. 74:12, ad Pompeium,) non solum doctus, sed etiam docibilis, quod in laude episcopi quem designat Apostolus sic intellexit ipse ut diceret: ‘etiam hoc in episcopo diligendum, ut non solum scienter doceat, sed etiam patienter discat.’” — , ad Pompeium,) non solum doctus, sed etiam docibilis, quod in laude episcopi quem designat Apostolus sic intellexit ipse ut diceret: ‘etiam hoc in episcopo diligendum, ut non solum scienter doceat, sed etiam patienter discat.’” — Aug. contra Donat, lib. 4:7, vol. 9:125., lib. 4:7, vol. 9:125.

²⁰³ “Mais il est vray-semblable, que Moyse l’a volontiers excuse pour sa vieillesse;” but it is probable that Moses voluntarily excused him on account of his old age. — Fr..