He maketh the deep to boil like a pot - In his rapid motion through it. The word "deep" (מצולה metsôlâh) may refer to any deep place - either of the sea, of a river, or of mire, Psalm 69:2. It is applied to the depths of the sea, Jonah 2:3; Micah 7:19; but there is nothing in the word that will prevent its application to a large river like the Nile - the usual abode of the crocodile.
He maketh the sea - The word "sea" (ים yâm) is often applied to a large river, like the Nile or the Euphrates; see the notes at Isaiah 19:5.
Like a pot of ointment - When it is mixed, or stirred together. Bochart supposes that there is an allusion here to the smell of musk, which it is said the crocodile has, and by which the waters through which he passes seem to be perfumed. But the allusion seems rather to be merely to the fact that the deep is agitated by him when he passes through it, as if it were stirred from the bottom like a pot of ointment.

He maketh the deep to boil like a pot - This is occasioned by strongly agitating the waters at or near the bottom; and the froth which arises to the top from this agitation may have the appearance of ointment. But several travelers say that the crocodile has a very strong scent of musk, and that he even imparts this smell to the water through which he passes, and therefore the text may be taken literally. This property of the crocodile has been noticed by several writers.

He maketh the deep to (k) boil like a pot: he maketh the sea like a pot of ointment.
(k) Either he makes the sea to seem like it is boiling by his wallowing, or else he spouts water in such abundance as it would seem that the sea boiled.

He maketh the deep to boil (k) like a pot,.... Which is all in a from through the violent agitation and motion of the waves, caused by its tossing and tumbling about; which better suits with the whale than the crocodile, whose motion in the water is not so vehement;
he maketh the sea like a pot of ointment; this also seems to make against the crocodile, which is a river fish, and is chiefly in the Nile. Lakes indeed are sometimes called seas, in which crocodiles are found; yea, they are also said to be in the seas, Ezekiel 32:2; and Pliny (l) speaks of them as common to the land, river, and sea; and the Nile is in the Alcoran (m) called the sea, and its ancient name was "Oceames" with the Egyptians, that is, in Greek, "ocean", as Diodorus Siculus (n) affirms; and so it is thought to be the Egyptian sea in Isaiah 11:15. It is observed that they leave a sweet scent behind them; thus Peter Martyr (o), in his account of the voyages of Columbus in the West Indies, says, they sometimes met with crocodiles, which, when they fled or took water, they left a very sweet savour behind them, sweeter than musk or castoreum. But this does not come up to the expression here of making the sea like a pot of ointment; but the sperm of the whale comes much nearer to it, which is of a fat oily nature, and like ointment, and which the whale sometimes throws out in great abundance, so that the sea is covered with it; whole pails full may be taken out of the water; it swims upon the sea like fat; abundance of it is seen in calm weather, so that it makes the sea all foul and slimy (p): and there are a sort of birds called "mallemuck", which fly in great numbers and feed upon it (q). I cannot but remark what the bishop of Bergen observes (r) of the sea serpent, that its excrements float on the water in summertime like fat slime.
(k) "Fervetque----aequor". Virgil. Georgic. l. 1. v. 327. (l) Nat. Hist. l. 32. c. 11. (m) Schultens in Job, xiv. 11. (n) Bibliothec. l. 1. p. 17. (o) Decad. 3. l. 4. (p) Voyage to Spitzbergen, p. 148, 149. (q) Vid. Scheuchzer. ut supra, (vol. 4.) p. 852. & Voyage to Spitzbergen, p. 167. (r) Pantoppidan's History of Norway, part 2. p. 204.

Whenever he moves.
sea--the Nile (Isaiah 19:5; Nahum 3:8).
pot of ointment--the vessel in which it is mixed. Appropriate to the crocodile, which emits a musky smell.

Boil - To swell, and foam, and froth by his strong and vehement motion, as any liquor does when it is boiled in a pot, especially boiling ointment. The sea - The great river Nile, is called a sea, both in scripture, as Isaiah 11:15, and in other authors, as Euphrates is called the sea of Babylon, Isaiah 21:1; Jeremiah 51:36. Lakes also are most frequently called seas both in the Old and New Testament: and in such lakes the crocodiles are as well as in the Nile.