Targum Psalm 104:26
24 How many are your works, O Lord! You have made all of them in wisdom; the earth is full of your possessions. 25 This sea is great and broad in extent; creeping things are there without number, both tiny creatures and large. 26 There the ships go about, [and] this Leviathan you created for the sport of the righteous at the supper of his dwelling place. 27 All of them rely on you to give their food in its time. 28 You will give it to them, and they gather it; you will open your hand, and they are satisfied with goodness.
Leviticus Rabbah 13:3Aggadah
R. Judan b. R. Simeon said: Behemoth and the Leviathan are to engage in a wild-beast contest before the righteous in the Time to Come, and whoever has not been a spectator at the wild-beast contests of the heathen nations in this world will be accorded the boon of seeing one in the World to Come. How will they be slaughtered? Behemoth will, with its horns, pull Leviathan down and rend it, and Leviathan will, with its fins, pull Behemoth down and pierce it through. The Sages said: And is this a valid method of slaughter? Have we not learnt the following in a Mishnah: All may slaughter, and one may slaughter at all times [of the day], and with any instrument except with a scythe, or with a saw,’ or with teeth [in a jaw cut out of a dead animal], because they cause pain as if by choking, or with a nail [of a living body]? R. Abin b. Kahana said: The Holy One, blessed be He, said: Instruction [Torah] shall go forth from Me (Isa. 11, 4), i.e. an exceptional temporary ruling® will go forth from Me.
Notes and References
"... The Targum on Psalms 104:25-26 appears also to be familiar with the theme of the eschatological contest, when it describes how Leviathan was created in order to “sport” at the banquet of the righteous. The midrashim is also familiar with this motif. From Leviticus Rabbah 13:3, one learns ... Pesikta de Rav Kahana (Sup. II.4) also knows about the eschatological fight between the two biblical monsters ..."
Orlov, Andrei Fight between Leviathan and Behemoth in the Messianic Time (pp. 1-12) Marquette University, 2022