But let us die, go plunging into the thick of battle.
One hope saves the defeated: they know they can’t be saved!

[Moriamur et in media arma ruamus.
Una salus victis, nullam sperare salutem.]

Virgil (70-19 BC) Roman poet [b. Publius Vergilius Maro; also Vergil]
The Aeneid [Ænē̆is], Book 2, l. 353ff (2.353-354) [Aeneas] (29-19 BC) [tr. Fagles (2006), l. 443ff]
    (Source)

(Source (Latin)). Alternate translations:

Then let us fall, but fall amidst our foes:
Despair of life the means of living shows.
[tr. Dryden (1697)]

Let us meet death, and rush into the thickest of our armed foes. The only safety for the vanquished is to throw away all hopes of safety.
[tr. Davidson/Buckley (1854)]

Come -- rush we on our fate.
No safety may the vanquished find
Till hope of safety be resigned.
[tr. Conington (1866)]

Let us die,
And plunge into the middle of the fight.
The only safety of the vanquished is
To hope for none.
[tr. Cranch (1872)]

Let us die, and rush on their encircling weapons. The conquered have one safety, to hope for none.
[tr. Mackail (1885)]

Fall on a very midst the fire and die in press of war!
One hope there is for vanquished men, to cherish hope no more.
[tr. Morris (1900)]

Forward, then,
To die and mingle in the tumult's blare.
Sole hope to vanquished men of safety is despair.
[tr. Taylor (1907), st. 47, l. 421ff]

Let us fight
unto the death! To arms, my men, to arms!
The single hope and stay of desperate men
is their despair.
[tr. Williams (1910)]

Let us die, and rush into the midst of arms. One safety the vanquished have, to hope for none!
[tr. Fairclough (1916)]

So let us die,
Rush into arms. One safety for the vanquished
Is to have hope of none.
[tr. Humphries (1951)]

Let us die, let us charge into the battle's heart!
Losers have one salvation -- to give up all hope of salvation.
[tr. Day Lewis (1952)]

Then let
us rush to arms and die. The lost have only
this one deliverance: to hope for none.
[tr. Mandelbaum (1971), l. 477ff]

Come, let us die,
We'll make a rush into the thick of it.
The conquered have one safety: hope for none.
[tr. Fitzgerald (1981), l. 470ff]

Let us die. Let us rush into the thick of the fighting. The one safety for the defeated is to have no hope of safety.
[tr. West (1990)]

All that is left for us
Is to rush onto swords and die. The only chance
For the conquered is to hope for none.
[tr. Lombardo (2005)]

Let us die even as we rush into the thick of the fight. The only safe course for the defeated is to expect no safety.
[Routledge (2005)]

Let's die by plunging into war. Our only refuge is to have no hope of refuge.
[tr. Bartsch (2021)]