Matthew Poole and continuators on Job 40:17

17. He moveth his tail like a cedar: the sinews of his stones are wrapt together.

Which though it be but short both in the Elephant and in the Hippopotamus, yet when it is erected is exceeding stiff and strong. But this may be understood, either 1. of his generative part, which is oft called by that or the like name, which the following Clause of the Verse may seem to favour. Or 2. of the Elephants trunk, which being so eminent and remarkable a part would not probably be omitted in this description, to which these words very fitly agree, because of its admirable motion and strength. Not is it strange that this is called his Tail, because that word is oft used improperly for any end of a thing, as Isa. 7. 4. See also Deut. 25. 18. & 28. 13, 44.

This may be noted because the Elephants Testicles do not hang down below the belly, as they do in other Beasts, but are contained within his belly, where they are fastned by Ligaments of extraordinary strength. Or, the Sinews of the terror thereof, to wit, of the Trunk last mentioned under the name of the Tail, i. e. its terrible Sinews are strongly and strangely wrapped together that he can move it as he listeth with wonderful dexterity and strength. Or, the Sinews of his Thighs, as the latter word oft signifies in the Arabic Tongue which is very near akin to the Hebrew. The Thighs and Feet of the Hippopotamus are noted to be so sinewy and strong that one of them is able to break or overturn a large Boat.

Marginal references: Or, [illegible: 1 word] [illegible: 1 word].