Matthew Poole and continuators on Job 39:3

3. They bow themselves , they bring forth their young ones , they cast out their sorrows .

Being taught by a Divine instinct to dispose themselves in such a posture as may be fittest for their safe and easie bringing forth.

To wit, with great pain being almost torn or rent asunder with the Birth, as the word signifies: or without any of that help, which tame Beasts oft have.

i. e. Their young ones and their sorrows together. Or, though (which Particle is oft understood) they remit or put away their sorrows, i. e. Though in stead of cherishing and furthering their sorrows, which for their own ease and safety they should do, they foolishly hinder them and so increase their own danger, yet by God's good Providence to them they are enabled to bring forth, as was now said.