29 You crushed the heads of Leviathan. The imagery of vv. 13–14 originates in West Semitic mythology. The description of Leviathan should be compared with the following excerpts from Ugaritic mythological texts: (1) “Was not the dragon [Ugaritic tnn, cognate with Hebrew תַּנִין (tanin), translated “sea monster” in v. 13] vanquished and captured? I did destroy the wriggling [Ugaritic ’qltn, cognate to Hebrew עֲקַלָּתוֹן (’aqallaton), translated “squirming” in Isa 27:1] serpent, the tyrant with seven heads” (note the use of the plural “heads” here and in v. 13). (See 3.iii.38–39 in G. R. Driver, Canaanite Myths and Legends, 50.) (2) “For all that you smote Leviathan the slippery [Ugaritic brh, cognate to Hebrew בָּרִחַ (bariakh), translated “fast moving” in Isa 27:1] serpent, [and] made an end of the wriggling serpent, the tyrant with seven heads” (See 5.i.1–3 in G. R. Driver, Canaanite Myths and Legends, 68.) In the myths Leviathan is a sea creature that symbolizes the destructive water of the sea and, in turn, the forces of chaos that threaten the established order. In the OT, the battle with the sea motif is applied to Yahweh’s victories over the forces of chaos at creation and in history (see Pss 74:13–14; 77:16–20; 89:9–10; Isa 51:9–10). Yahweh’s subjugation of the waters of chaos is related to his kingship (see Pss 29:3, 10; 93:3–4). Isa 27:1 applies imagery from Canaanite mythology to Yahweh’s eschatological victory over his enemies. Apocalyptic literature employs the imagery as well. The beasts of Dan 7 emerge from the sea, while Rev 13 speaks of a seven-headed beast coming from the sea. Here in Ps 74:13–14 the primary referent is unclear. The psalmist may be describing God’s creation of the world (note vv. 16–17 and see Ps 89:9–12), when he brought order out of a watery mass, or the exodus (see Isa 51:9–10), when he created Israel by destroying the Egyptians in the waters of the sea.
30 The prefixed verbal form is understood as a preterite in this narrational context.
31 You fed him to the people. This pictures the fragments of Leviathan’s dead corpse washing up on shore and being devoured by those who find them. If the exodus is in view, then it may allude to the bodies of the dead Egyptians which washed up on the shore of the Red Sea (see Exod 14:30).