The Psalm itself was, it may be concluded from internal evidence, composed just after the destruction of Solomon's Temple, and the carrying of Israel captive to Babylon, hence it becomes a fitting vehicle for expressing the mind of the people of God when suffering at the hands of their enemies...
...sung by the Protestants of the Vaud, while marching into Geneva in 1686... (death of the witnesses Rev 11:8)
"Even among the Alps liberty of singing Psalms was denied. The Protestants of the Vaud were driven from their homes and dispossessed of their property. The exiles, diminished in number by the hardships of a winter journey across the Alps, with voices choked by exhaustion and misery, sang Psalm 74
(The Berean Christadelphian, May 1923)
13 Thou didst divide the sea by thy strength: thou brakest <shivbarta> the heads of the dragons in the waters.
14 Thou brakest <ritzatva> the heads of leviathan in pieces, and gavest him to be meat to the people inhabiting the wilderness.
..In reference to the dragon-heads the word used is shivbarta; while the other is ritzatva. This verbal difference was doubtless not accidental. The former signifies "to break the power of, destroy;" the latter, "to bruise. " Leviathan is bruised and bound for a thousand years, and at the end thereof revives, and embraces the serpent-world in his coils: but the power of the dragons and their heads in the long interval antecedent to the epoch of the binding, is destroyed.
...The Scriptures oftentimes connect the beginning and the end without taking cognizance of the interval of a multitude of generations and ages, or, if at all, only very slightly. Thus, in Psa. 74:12, the Mosaic salvation from Egyptian bondage, and the future Messianic salvation from the down-treading of the mystic Babylon, apocalyptically and "spiritually called Sodom and Egypt" (Apoc ch. 11:3), are so connected: as it is written,
"My King of old is Elohim, working salvation in the midst of the earth. Thou didst divide the sea by thy strength."
Then, predictive of what will assuredly come to pass, and befall the same Serpent-power in its latter-day manifestation, as apocalyptically displayed in the binding of the Dragon, it proceeds in verse 14 to state,
"Thou bruisedst the heads of leviathan, and gavest him to be meat to the people inhabiting the wilderness."
LEVIATHAN signifying "a serpent coiling himself in folds," is the Dragon of Apoc. 20:2; and embraces all the intermediate dragonic manifestations of previous ages and generations, which are the folds of his coil. The "heads of leviathan" are those apocalyptically exhibited. "The people inhabiting the wilderness" are the saints, and Israel after the flesh made willingly subject to them.
"The wilderness" is "the two wings of the Great Eagle" where the fugitive woman was fed and "nourished for a time, times, and half a time from the face of the serpent," or, for 1260 symbolic days (Apoc. 12:6,14); and where John saw Leviathan as he will be seen by the discerning after the thief-like advent of the Ancient of Days (ch. 17:3).
...Now there have been different dragon-manifestations of "the old serpent" in the long interval between the Mosaic salvation of Israel and the Messianic, which is at the door. That contemporary with Moses, and styled "Rahab" in Isa. 51:9, was developed into what Ezekiel describes in ch. 29:3.
Here the power of Egypt, called Pharaoh, is thus addressed by the Spirit,
"Behold I am against thee, Pharaoh, King of Egypt, THE GREAT DRAGON that lieth in the midst of his rivers" - the mouths of the Nile, representative of the subjects of the power: "which hath said, My river is my own, and I have made it for myself."
For this arrogance, and blasphemy against the source of all power, YAHWEH Elohim sentenced it to destruction, so that Egypt should no more exalt itself above the nations to rule over them; and, as Nebuchadnezzar had received no recompense for executing the sentence of Deity against Tyre, therefore YAHWEH Elohim gave the land of Egypt to him for his labour.