Why did the knees prevent me? - That is, the lap of the nurse or of the mother, probably the latter. The sense is, that if he had not been delicately and tenderly nursed, he would have died at once. He came helpless into the world, and but for the attention of others he would have soon died. Jahn supposes (Archae section 161) that it was a common custom for the father, on the birth of a son, to clasp the new-born child to his bosom, while music was heard to sound, and by this ceremony to declare it as his own. That there was some such recognition of a child or expression of paternal regard, is apparent from Genesis 50:23. Probably, however, the whole sense of the passage is expressed by the tender care which is necessarily shown to the new-born infant to preserve it alive. The word rendered "prevent" here קדם qâdam, means properly to anticipate, to go before, as the English word "prevent" formerly did; and hence, it means to go to meet anyone in order to aid him in any way. There is much beauty in the word here. It refers to the provision which God has made in the tender affection of the parent to "anticipate" the needs of the child. The arrangement has been made beforehand. God has taken care when the feeble and helpless infant is born, that tender affection has been already created and prepared to meet it. It has not to be created then; it is not to be excited by the suffering of the child; it is already in existence as an active, powerful, and self-denying principle, to "anticipate" the needs of the newborn babe, and to save it from death.

Why did the knees prevent me? - Why was I dandled on the knees? Why was I nourished by the breasts? In either of the above cases I had neither been received into a mother's lap, nor hung upon a mother's breasts.

Why did the knees prevent me?.... Not of the mother, as Jarchi, but of the midwife, who received him into her lap, and nourished and cherished him, washed him with water, salted, and swaddled him; or it may be of his father, with whom it was usual to take the child on his knees as soon as born, see Genesis 50:23; which custom obtained among the Greeks and Romans (o); hence the goddess Levana (p) had her name, causing the father in this way to own his child; his concern is, that he did not fall to the ground as he came out of his mother's womb, and with that fall die; and that he was prevented from falling by the officious knees of the midwife; that he was not suffered to fall, and be left there, without having any of the usual things done to him for the comfort and preservation of life, which was sometimes the case, Ezekiel 16:4,
or why the breasts that I should suck? since a miscarrying womb was not given, and death did not seize him immediately upon birth, but all proper care was taken to prevent it, he asks, why was there milk in the breasts of his mother or nurse to suckle and nourish him? why were there not dry breasts, such as would afford no milk, that so he might have been starved? thus he wishes the kindest things in nature and Providence had been withheld from him.
(o) Homer. Iliad. 9. Vid. Barthii Animadv. ad Claudian. in Nupt. Honor. ver. 341. (p) Kipping. Antiqu. Roman. l. 1. c. 1. sect. 10.

Why did the knees prevent me?--Old English for "anticipate my wants." The reference is to the solemn recognition of a new-born child by the father, who used to place it on his knees as his own, whom he was bound to rear (Genesis 30:3; Genesis 50:23; Isaiah 66:12).

The knees - Why did the midwife or nurse receive and lay me upon her knees, and not suffer me to fall upon the bare ground, 'till death had taken me out of this miserable world, into which their cruel kindness hath betrayed me? Why did the breasts prevent me from perishing through hunger, or supply me that should have what to suck? Thus Job unthankfully despises these wonderful mercies of God towards poor helpless infants.