The Bible refers to the unicorn in the context of familiar animals, such as peacocks, lambs, lions, bullocks, goats, donkeys, horses, dogs, eagles, and calves (
Job 39:912).
1 In Job 3841, God reminded Job of the characteristics of a variety of impressive animals He had created, showing Job that God was far above man in power and strength.
2
Job had to be familiar with the animals on Gods list for the illustration to be effective. God points out in
Job 39:912 that the unicorn, whose strength is great, is useless for agricultural work, refusing to serve man or harrow (plow) the valley. This visual aid gave Job a glimpse of Gods greatness. An imaginary fantasy animal would have defeated the purpose of Gods illustration.
Modern readers have trouble with the Bibles unicorns because we forget that a single-horned feature is not uncommon on Gods menu for animal design. (Consider the rhinoceros and narwhal.) The Bible describes unicorns skipping like calves (
Psalm 29:6), traveling like bullocks, and bleeding when they die (
Isaiah 34:7). The presence of a very strong horn on this powerful, independent-minded creature is intended to make readers think of strength.
The absence of a unicorn in the modern world should not cause us to doubt its past existence. (Think of the dodo bird. It does not exist today, but we do not doubt that it existed in the past.). Eighteenth century reports from southern Africa described rock drawings and eyewitness accounts of fierce, single-horned, equine-like animals. One such report describes a single horn, directly in front, about as long as ones arm, and at the base about as thick . . . . [It] had a sharp point; it was not attached to the bone of the forehead, but fixed only in the skin.
Source:
https://answersingenesis.org/bible-questions/unicorns-in-the-bible/
