Gregory the Dialogist

He setteth fast his tail, like a cedar. 22. There are in these words many points, to be brought forward for moral instruction. But we examine in the first place the violences of this Behemoth, in order afterwards to detect more accurately his crafts. In Holy Scripture under the name 'cedar,' sometimes the lofty excellence of heavenly glory is expressed; but sometimes the stubborn pride of the wicked is designated. …

Morals on the Book of Job, Book XXXII ↗

Thomas Aquinas

Animals who perform coitus of this kind press the tail between their legs when they perform the sexual act, and so he says, "He stiffens his tail like a cedar," which he says because of its great size. Third, he describes the organs serving coitus when he says, "the sinews of his testicles are joined together," that is, they twist, as the Philosopher says in The History of Animals III about the testicles of all animals who walk and generate other animals. …

Commentary on Job ↗

Bonaventure

In the twelfth mystery, the opening of scriptures, the Antichrist is symbolized by the beast from the depth, the one that comes up out of the abyss, who will crush all things. For he will be consummate in every form of malice; he will have seven heads, that is, every kind of temptation and every method, working at times through riches, at other times through false miracles, at others again through fear. Hence in Job: "He carries his tail like a cedar," for in him every form of malice will be inflated. …

Collations on the Hexaemeron, Collation 15 ↗