and I say to you, “Let my son go that he may serve me.” If you refuse to let him go, behold, I will kill your firstborn son.’”
23. And I say unto thee, Let my son go. This was not the beginning of the legation, but its final clause; for Moses warned the desperate man of his son’s death, when everything else had been tried in vain. The meaning is, then, that the obstinacy of the tyrant must not prevent Moses from pressing him even to this final act.
Moses honored his father-in-law by asking leave before departing, showing that divine commission does not free us from the duties we owe in our station. God knew the secret fear that held him back, dread of his old enemies, and assured him the way was clear.
AI summary
Commenting on Exodus 4:18-23
And I say unto thee, let my son go, that he may serve me,.... Worship God according to his will in the place he had designed for him, and where he might be safe and free; and which service was due from him as a son, and to be performed not in a servile way, but in a filial manner, and therefore as a servant...