Hear now the treachery of the Greeks and from one learn the wickedness of all.

[Accipe nunc Danaum insidias, et crimine ab uno
Disce omnes.]

Virgil (70-19 BC) Roman poet [b. Publius Vergilius Maro; also Vergil]

The Aeneid [Ænē̆is], Book 2, l. 65ff (2.65-66) [Aeneas] (29-19 BC) [tr. Fairclough (1916)]
    (Source)

Regarding Sinon, who posed as a Greek refugee and persuaded the Trojans that the Trojan Horse was harmless. (Source (Latin)). Alternate translations:

Receive Greeks treacheries now; and from one crime
Learn all.
[tr. Ogilby (1649)]

Now hear how well the Greeks their wiles disguis'd;
Behold a nation in a man compris'd.
[tr. Dryden (1697)]

Now learn the treachery of the Greeks, and from one crime take a specimen of the whole nation.
[tr. Davidson/Buckley (1854), "Literally, 'from one of their tricks learn what they all are.'"]

Now listen while my tongue declares
The tale you ask of Danaan snares,
And gather from a single charge
Their catalogue of crimes at large.
[tr. Conington (1866)]

Now
Hear what the treachery of the Grecians was,
And from one crime learn all.
[tr. Cranch (1872), l. 89ff]

Know now the treachery of the Grecians, and from a single crime learn all.
[tr. Mackail (1885)]

Lo now, behold the Danaan guile, and from one wrong they wrought
Learn ye what all are like to be.
[tr. Morris (1900)]

Mark now the Danaans' cunning; from one wrong
Learn all.
[tr. Taylor (1907), st. 10, ll. 82-83]

Hear now what Greek deception is, and learn
from one dark wickedness the whole.
[tr. Williams (1910)]

Listen, and learn Greek trickiness; learn all
Their crimes from one.
[tr. Humphries (1951)]

Now hear how the Greeks tricked us; learn from one case of their wickedness
What every Greek is like.
[tr. Day Lewis (1952)]

Now listen to the treachery of the Danaans
and learn from one the wickedness of all.
[tr. Mandelbaum (1971), ll. 92-93]

Be instructed now
In Greek deceptive arts: one barefaced deed
Can tell you of them all.
[tr. Fitzgerald (1981), l.91ff]

Listen now to this story of Greek treachery, and from this one indictment, learn the ways of a whole people.
[tr. West (1990)]

Listen now to Greek treachery, and learn of all their crimes
from just this one.
[tr. Kline (2002)]

Hear now
The treachery of the Greeks, and from one offense
Learn all their evil.
[tr. Lombardo (2005)]

Now, hear the treachery of the Greeks and learn
from a single crime the nature of the beast.
[tr. Fagles (2006)]

Now hear how the Greeks baited their trap, and from one act of treachery, understand them all!
[tr. Bartsch (2021)]