Adam Clarke on Job 15:33

He shall shake off his unripe grape -

10. Whatever children he may have, they shall never survive him, nor come to mature age. They shall be like wind-fall grapes and blasted olive blossoms. As the vine and olive, which are among the most useful trees, affording wine and oil, so necessary for the worship of God and the comfort of man, are mentioned here, they may be intended to refer to the hopeful progeny of the oppressor; but who fell, like the untimely grape or the blasted olive flower, without having the opportunity of realizing the public expectation.