It is dangerous to attack a man whom you have deprived of every means of escape except by fighting, for necessity is a violent schoolmistress.

[Il fait dangereux assaillir un homme, à qui vous avez osté tout autre moyen d’eschapper que par les armes : car c’est une violente maistresse d’escole que la necessité.]

Michel de Montaigne (1533-1592) French essayist
Essays, Book 1, ch. 47 (1.47), “Of the Uncertainty of Our Judgment [De l’incertitude de nostre jugement]” (1572) [tr. Cohen (1958)]
    (Source)

This essay was present in the 1st (1580) edition, and was expanded for each succeeding edition. This particular passage remained unchanged.

(Source (French)). Alternate translations:

It is dangerous to assaile a man, whom you have bereaved of all other meanes to escape or shift for himselfe, but by his weapons: for, necessitie is a violent schoole-mistris, and which teacheth strange lessons.
[tr. Florio (1603)]

It is dangerous to attack a man you have deprived of all means to escape, but by his arms; for necessity dictates violent measures.
[tr. Cotton (1686)]

’Tis dangerous to attack a man you have deprived of all means to escape but by his arms, for necessity teaches violent resolutions.
[tr. Cotton/Hazlitt (1877)]

It is dangerous to attack a man whom you have deprived of any other means of escape than fighting; for an impetuous schoolmistress is necessity.
[tr. Ives (1925)]

It is dangerous to attack a man whom you have deprived of every other means of escape but that of weapons; for necessity is a violent schoolmistress.
[tr. Frame (1943)]

It is hazardous to go and attack a man when you have deprived him of all means of escape save his weapons, for Necessity is a ferocious teacher.
[tr. Screech (1987)]