Albert Barnes Commentary Job 39:4

"Their young ones become strong, they grow up in the open field; They go forth, and return not again." — Job 39:4 (ASV)

Their young ones are in good liking – in Hebrew, "they are fat"; and thus, it means that they are strong and robust.

They grow up with corn – Herder, Gesenius, Noyes, Umbreit, and Rosenmuller translate this as "in the wilderness," or "field." The proper and usual meaning of the word used here (בר bâr) is corn (grain); but in Chaldee it has the sense of open fields, or country. The same idea is found in the Arabic, and this meaning seems to be required by the connection. The idea is not that they are nurtured with grain, which would require human care, but that they are nurtured under the direct eye of God far from human dwellings, even when they go away from their mother and do not return to the place of their birth.

This is one of the instances, therefore, in which the connection seems to require us to adopt a meaning that does not occur elsewhere in Hebrew, but which is found in the cognate languages.

They go forth, and return not unto them – God guards and preserves them, even when they wander away from their mother and are left helpless. Many young animals require long attention from humans; many are kept for a considerable period by the mother's side. However, the idea here seems to be that the young of the wild goat and the fawn are entrusted early to God's providence and are protected by Him alone. The particular care of Providence over these animals seems to be specified because no others are exposed to so many dangers in their early life.

"Every creature then is a formidable enemy. The eagle, the falcon, the osprey, the wolf, the dog, and all the rapacious animals of the cat family, are continually seeking to find their retreat. But what is more unnatural still, the stag himself is a professed enemy, and she, the hind, is obliged to use all her skills to conceal her young from him, as from the most dangerous of her pursuers." (Goldsmith’s Nat. His.)