The phrase “eat, drink, and be merry, for tomorrow we die” is a proverbial description for a careless approach to the future. Nephi uses it to describe those who believe that Yahweh has accomplished his major task. Therefore, there is nothing to look forward to. There is no future redemption, for the redemption has already occurred. They need not worry about a future judgment, for they are already “saved.” Nephi presents this argument satirically as positive, but embracing such an obviously incorrect position only highlights its incongruity. It nearly refutes itself, although Nephi will continue to deride the faulty thinking that holds such a concept.
Reference: “Eat, drink, and be merry” occurs in various locations in the Old Testament. In Ecclesiastes 8:14–15 it appears in an apparently positive context:
There is a vanity which is done upon the earth; that there be just men, unto whom it happeneth according to the work of the wicked; again, there be wicked men, to whom it happeneth according to the work of the righteous: I said that this also is vanity.
Then I commended mirth, because a man hath no better thing under the sun, than to eat, and to drink, and to be merry: for that shall abide with him of his labour the days of his life, which God giveth him under the sun.
Ecclesiastes recommends concentrating on the present moment rather than the future because the world is full of inequities (v. 14). Therefore, one must take joy where one can. By bracketing out any discussion of a future life or eternal redemption, Ecclesiastes counsels, “Eat, drink, be merry” as an affirmation of life—a way to live joyfully in spite of surrounding inequities.
Isaiah also expresses the idea of eating and drinking in the face of inevitable death but, in contrast to Ecclesiastes, Isaiah contrasts this approach to righteous living:
Ye made also a ditch between the two walls for the water of the old pool: but ye have not looked unto the maker thereof, neither had respect unto him that fashioned it long ago.
And in that day did the Lord God of hosts call to weeping, and to mourning, and to baldness, and to girding with sackcloth:
And behold joy and gladness, slaying oxen, and killing sheep, eating flesh, and drinking wine: let us eat and drink; for to morrow we shall die.
And it was revealed in mine ears by the Lord of hosts, Surely this iniquity shall not be purged from you till ye die, saith the Lord God of hosts. (Isa. 22:11–14)
Isaiah 22:11 describes Jerusalem’s preparations for a siege, in particular caring for the pool that will provide its water. However, Yahweh notes that while they care for the pool, they neglect the one who created it. Wayward Judah pays attention to the things of the world while ignoring the things of the Spirit.
The contrast is heightened in verses 12–13. Yahweh commands weeping and mourning (meaning repentance and humility), but instead the people are eating and drinking. The eating and drinking is still in the context used by Ecclesiastes—that of daily living. Rather than repenting, Jerusalem continues as if everything were the same. It does not see the error of its ways and return to Yahweh.
The “tomorrow we die” phrase highlights the temporal vision of the people. Note that Isaiah omits “merry” from his description. He is not contrasting a “merry” people with his desired repentant people, but rather their lack of focus on the things of the Spirit—those things which pertain to more than “tomorrow.”
Nephi is following Isaiah’s usage, though with the addition of the “merry.” The concept still contrasts a quotidian focus with an eschatological focus.