Genesis 30:9

9.When Leah saw that she had left bearing. Moses returns to Leah, who, not content with four sons, devised a method whereby she might always retain her superior rank: and therefore she also, in turn, substitutes her maid in her place. And truly Rachel deserved such a reward of her perverse design; since she, desiring to snatch the palm from her sister, does not consider that the same contrivance to which she had resorted, might speedily be employed against herself. Yet Leah sins still more grievously, by using wicked and unjust arts in the contest. Within a short period, she had experienced the wonderful blessing of God; and now, because she ceased from bearing, for a little while, she despairs concerning the future, as if she had never participated in the Divine favor. What, if her desire was strong; why did she not resort to the fountain of blessing? In obtruding, therefore, her maid, she gave proof not only of impatience, but also of distrust; because with the remembrance of Divine mercy, faith also is extinguished in her heart. And we know that all who rely upon the Lord are so tranquil and sedate in their mind, that they patiently wait for what he is about to give. And it is the just punishment of unbelief when any one stumbles through excessive haste. So much the more ought we to beware of the assaults of the flesh, if we desire to maintain a right course.

As to the name Gad, this passage is variously expounded by commentators. In this point they agree, that בגד (bagad) means the same as if Leah had said “the time of bearing is come.” (76) But some suppose גד (Gad,) to be the prosperous star of Jupiter; others, Mercury; others, good fortune. They adduce Isaiah 65:11, where it is written, “they offer a libation to Gad.” (77) But the context of the Prophet shows that this ought rather to be understood of the host of heaven, or of the number of false gods; because it immediately follows that they offer sacrifices to the stars, and furnish tables for a multitude of gods: the punishment is then added, that as they had fabricated an immense number of deities, so God will “number” them “to the sword.” As it respects the present passage, nothing is less probable than that Leah should extol the planet Jupiter instead of God, seeing that she, at least, maintained the principle that the propagation of the human race flows from God alone. I wonder also that interpreters understand this of prosperous fortune, when Moses afterwards, Genesis 49:19, leads us to an opposite meaning. For the allusion he there makes would be inappropriate, “Gad, a troop shall overcome him,” etc., unless it had been the design of Leah to congratulate herself on the troop of her children. For since she had so far surpassed her sister, (78) she declares that she has children in great abundance. When she proclaims herself happy (79) in her sixth son, it again appears in what great esteem fecundity was then held. And certainly it is a great honor, when God confers on mortals the sacred title of parents, and through them propagates the human race formed after his own image.