For when the faculty of intellect
is joined with brute force and with evil will,
no man can win against such an alliance.

[Ché dove l’argomento de la mente
s’aggiugne al mal volere e a la possa,
nessun riparo vi può far la gente.]

Dante Alighieri (1265-1321) Italian poet

The Divine Comedy [Divina Commedia], Book 1 “Inferno,” Canto 31, l. 55ff (31.55) (1309) [tr. Musa (1971)]
    (Source)

Why Nature no longer allows human-like giants, while still producing whales and elephants.

(Source (Italian)). Alternate translations:

For where the mind to bad Intention's join'd,
And with a Pow'r what's ill design'd to act,
None can himself from such a force defend.
[tr. Rogers (1782), l. 49ff]

But not the forest tribes, nor finny race,
With equal rage their native walks deface,
As he whose deadly arm by Reason's light
Directed falls, and mocks the warding hand;
Conspiring realms in vain his pow'r withstand,
In vain embattled hosts defend their right.
[tr. Boyd (1802), st. 9]

For when brute force
And evil will are back’d with subtlety,
Resistance none avails.
[tr. Cary (1814)]

For discourse of mind,
Wedded with power and inbred lust of wrong,
Had left nor help nor rescue for mankind.
[tr. Dayman (1843)]

For where [the instrument] of [the] mind is joined to evil will and potency, men can make no defence against it.
[tr. Carlyle (1849)]

For when a reasoning and a subtle mind
Is joined, besides, to evil will and power,
Who can resist? -- for all defence must cower.
[tr. Bannerman (1850)]

For when the reasoning faculty combines
With evil will and with destructive pow'r,
Then there remains no more defence for man.
[tr. Johnston (1867)]

For where the argument of intellect ⁠
⁠Is added unto evil will and power,
⁠No rampart can the people make against it.
[tr. Longfellow (1867)]

For where the equipment of the mind is joined to illwill and to power, folk can make no rampart against it.
[tr. Butler (1885)]

For where the assistance of the intellect
Is added unto evil will and power,
'Gainst it no refuge could mankind erect.
[tr. Minchin (1885)]

For where the faculty of the mind is added to evil will and to power, the human race can make no defense against it.
[tr. Norton (1892)]

For where the force of intellect is joined to evil will, and power to do such will, mankind is helpless to find resource against it.
[tr. Sullivan (1893)]

For, where the equipment and the use of reason
Are joined to ill intent and power of action,
No sort of refuge can folk make against it.
[tr. Griffith (1908)]

For where the equipment of the mind is joined to evil will and to power men can make no defence against it.
[tr. Sinclair (1939)]

For if with the mind's instrument unite
Power and an evil purpose both at once,
Men have no means against such force to fight.
[tr. Binyon (1943)]

For where the instrument of thinking mind
Is joined to strength and malice, man’s defence
Cannot avail to meet those powers combined.
[tr. Sayers (1949)]

For where the instrument of intelligence
is added to brute power and evil will,
mankind is powerless in its own defense.
[tr. Ciardi (1954)]

For where the instrument of the mind is added to an evil will and to great power, men can make no defense against it.
[tr. Singleton (1970)]

For where the mind’s acutest reasoning
is joined to evil will and evil power,
there human beings can’t defend themselves.
[tr. Mandelbaum (1980)]

For, where the argument of reason is
Joined with an evil will and potency,
There is no possible defence for man.
[tr. Sisson (1981)]

The power of the mind, along with that
Of immense strength, upon an evil will
Then people will have no defense from it.
[tr. Pinsky (1994), l. 52ff]

For where sharpness of mind is joined to evil will and power, there is no defence people can make against them.
[tr. Durling (1996)]

Where the instrument of mind is joined to ill will and power, men have no defence against it.
[tr. Kline (2002)]

For when the powers of working intellect
are wed to strength and absolute illwill,
then humans cannot find a place to hide.
[tr. Kirkpatrick (2006)]

For when the power of thought
is coupled with ill will and naked force
there is no refuge from it for mankind.
[tr. Hollander/Hollander (2007)]

For when the thinking powers of human brains
Are tools of malicious will and enormous strength,
Smaller creatures like men have no defense.
[tr. Raffel (2010)]

For only when ill will and massive strength
Are joined with mental power does it arise
That the invincible is born.
[tr. James (2013), l. 58ff]