John Gill's Exposition of the Whole Bible
Job 31:15
Did not he that made me in the womb make him?.... And her also, both his manservant and maidservant: these were made, by the Lord as Job was, and in a like place and manner as he himself; though parents are the instruments of begetting children, and of bringing them into the world, God is the Maker of men, as at the beginning, and all are alike made by him, in whatsoever rank, condition, and circumstance of life, whether masters or servants; and they are all fabricated in the same shop of nature, the womb of a woman:
and did not one fashion us in the womb? that is, he who is the one God, according to Malachi 2:10; God is one in nature and essence, though there are three Persons in the unity of the Godhead; and this one God, Father, Son, and Spirit, is the Creator of all men and things; hence we read of "Creators", Ecclesiastes 12:1; and, though one God makes the bodies and creates the souls of men now as at the first, and all are formed and fashioned by him, high, low, rich and poor, bond and free; and they have all the same rational powers and faculties of soul, Psalms 33:15; as well as the same curious art and skill are employed in forming and fashioning their bodies and the members of them, in the lower parts of the earth, in their mother's womb; yea, they are fashioned "in one womb" h, as the words will better bear to be rendered according to the position of them in the original and the accents; not indeed in the same identical womb, but in a like one: there are two words in the original here, both translated "womb"; the one signifies the "ovarium", in which the conception is made; the other designs the "secundine", in which the fetus is wrapped or covered; for so it may be rendered, "did he not cover us?" c. i though Jarchi, Aben Ezra, Ben Gersom, and others, interpret it of the one God as we do: Job's reasoning is, that seeing he and his servants were equally the workmanship of God, and both made in the womb by him, and curiously fashioned alike, and possessed of the same rational powers, it would be unreasonable in him to use them ill, who were his fellow creatures; and should he, he might expect the Maker of them both would highly resent it. Macrobius k, an Heathen writer, gives a remarkable instance of the care heaven, as he expresses it, has of servants, and how much the contempt of it is resented thereby; and reasons much in the same manner concerning them as Job does here, that they are men, though servants; are of the same original, breathe in the same air, live and die as other men.
h ברחם אחד εν τη αυτη κοιλια, Sept. "in utero uno", Munster; so Beza, Drusius, Michaelis. i Saturnal. l. 1. c. 11. k Vid. Hackman. Praecidan. Sacr. p. 193.