John Calvin Commentary Exodus 4:18

"And Moses went and returned to Jethro his father-in-law, and said unto him, Let me go, I pray thee, and return unto my brethren that are in Egypt, and see whether they be yet alive. And Jethro said to Moses, Go in peace." — Exodus 4:18 (ASV)

And Moses went. It is surprising that Moses suppressed the vision by which his father-in-law’s mind might have been most inclined to let him go. Instead, Moses spoke merely of human feelings, saying that he desired to revisit his brothers and relations.

Yet it must have been disagreeable to his father-in-law to lose his services, and the diligence and industry from which he had greatly profited. Nor could it have been pleasant to send away his daughter and grandchildren to a foreign country. Whether Moses was forbidden by God to mention the vision, or whether he was silent from fear and shame, is uncertain. However, I am more inclined to the supposition that he dared not speak of his calling, lest its incredibility should cause him to be suspected of falsehood and vanity.

Since, then, it would have been difficult for his calling to be believed, he preferred to use his natural affection as a pretext. But Jethro, being persuaded more by divine inspiration than by that excuse, was easily convinced. I have no doubt that for forty years Moses had given such proofs of his honesty that he was free from all evil suspicion. We know how much respect is gained by long experience. Therefore, since Moses had so long demonstrated his integrity, his father-in-law could have no fears of his frivolity, fraud, or deceit.

By this example, believers learn always to seek to obtain a good reputation, for there is nothing that so greatly facilitates the handling of all affairs as the constant course of an upright and innocent life.

For, why does so much difficulty arise in obtaining what each may want from his neighbor? Why are there such hindrances and such reproaches on both sides, if not because, while everyone wishes to be believed, no one works to gain trust through his integrity?

But although Moses had won over his father-in-law by his upright and holy life, he was still confirmed in his calling by the readiness with which his request was granted. For the permission was full of courtesy and kindness, without any sign of reluctance or regret.