Thou brakest the heads of leviathan in pieces - On the meaning of the word "leviathan," see the notes at Job 41:1. The word is used here as descriptive of sea monsters.
And gavest him to be meat - Gavest him for "food."
To the people inhabiting the wilderness - That is, the sea monsters were killed, and, being thrown on shore, were gathered for food. The "inhabitants of the wilderness" or the desert, may refer either to the wild and savage tribes of men that lived on the shores of the sea, and that subsisted mainly on fish, or it may refer to the wild animals of the desert that consumed such sea monsters as they were cast up on the shore. There is no allusion to the Israelites considered as passing through the desert, as if they had fed on these sea monsters. The essential idea is, that these monsters were put to death, or were so removed but of the way as to offer no obstruction to the passage of the Israelites through the sea. It was as if they had been killed. The image is entirely poetic, and there is no necessity for supposing that such a thing literally occurred.

The heads of leviathan - Leviathan might be intended here as a personification of the Egypttan government; and its heads, Pharaoh and his chief captains.
To the people inhabiting the wilderness - Probably meaning the birds and beasts of prey. These were the people of the wilderness, which fed on the dead bodies of the Egyptians, which the tides had cast ashore. The Vulgate, Septuagint, Ethiopic, and Arabic read, "Thou hast given him for meat to the Ethiopians," or Abyssinians.

Thou brakest the heads of (k) leviathan in pieces, [and] gavest him [to be] (l) meat to the people inhabiting the wilderness.
(k) Which was a great monster of the sea, or whale, meaning Pharaoh.
(l) His destruction rejoiced them as meat refreshes the body.

Thou breakest the heads of leviathan in pieces,.... A large fish, generally thought to be the whale, by some the crocodile, described in Job 41:1 to which the king of Egypt or Babylon is compared, Isaiah 27:1 and so the Romish antichrist in one of his characters is represented as a sea beast with many heads, which will all be broken in pieces in due time, Revelation 13:1, as here is one "leviathan" with heads in the plural number. Aben Ezra thinks the word is wanting, and may be supplied thus, "thou hast broken the heads of every leviathan"; it may be interpreted as before of Pharaoh and his chief men; so the Targum,
"thou hast broken the heads of the mighty men of Pharaoh:''
and gavest him to be meat to the people inhabiting the wilderness; either to the wild beasts, called "tziim", the word here used, Isaiah 13:21 and may be called a people, as the ants and coneys are, Proverbs 30:25, to whom the dead bodies of Pharaoh and his host, drowned in the Red sea, were given for food, when they were cast upon the shore, where the Israelites saw them dead, Exodus 14:28, or to the "Ichthyophagy", a sort of people that dwelt by the Red sea, and lived on fishes; and so the Egyptians became their food, they living upon the fish which devoured their bodies, at least some of them: the Septuagint, Vulgate Latin, Ethiopic, and Arabic versions, render it, "to the people", the Ethiopians; who, it seems, living upon the borders of Egypt, took this opportunity, when Pharaoh and his host were drowned, and seized upon their country; but others refer it to the people of Israel themselves, as the Targum,
"thou hast given them for destruction to the people of the house of Israel, and their bodies to the dragons;''
and so Jarchi,
"thou hast given his mammon or riches to the people of Israel, to feed their companies and armies;''
and Kimchi interprets it of the spoil of the sea which the Israelites took from them; and they may be truly called the people inhabiting the wilderness, since they were in one forty years; so the Romish "leviathan", or antichristian whore, will be given to the Christian kings, who will hate her, eat her flesh, and burn her with fire; and to the Christian church, which now is in the wilderness, where it is nourished for a time and times, and half a time.

heads of leviathan--The word is a collective, and so used for many.
the people . . . wilderness--that is, wild beasts, as conies (Proverbs 30:25-26), are called a people. Others take the passages literally, that the sea monsters thrown out on dry land were food for the wandering Arabs.

Leviathan - Pharaoh. The people - To the ravenous birds and beasts of the desert. These creatures are significantly called the people of the wilderness, because they are the only people that inhabit it.