‘Tis for little Souls, that truckle under the Weight of Affairs, not to know how clearly to disengage themselves, and not to know how to lay them aside, and take them up again.
 
[C’est aux petites ames ensevelies du poix des affaires, de ne s’en sçavoir purement desmesler : de ne les sçavoir et laisser et reprendre.]

Michel de Montaigne (1533-1592) French essayist
Essays, Book 3, ch. 13 “On Experience [De l’Experience]” (1588) (3.13) (1595) [tr. Cotton (1686)]
    (Source)

(Source (French)). Alternate translations:

It is for base and pettie mindes, dulled and overwhelmed with the weight of affaires, to be ignorant how to leave them, and not to know how to free themselves from them; nor how to leave and take them againe.
[tr. Florio (1603)]

’Tis for little souls, that truckle under the weight of affairs, not from them to know how clearly to disengage themselves, not to know how to lay them aside and take them up again.
[tr. Cotton/Hazlitt (1877)]

It is for small souls, buried under the weight of affairs, not to know how to free themselves therefrom entirely; not to know how to leave them and return to them.
[tr. Ives (1925)]

It is for little souls, buried under the weight of business, to be unable to detach themselves cleanly from it or to leave it and pick it up again.
[tr. Frame (1943)]

It is for petty souls overwhelmed by the weight of affairs to be unable to disentangle themselves for them completely, not knowing how to drop them and then take them up again.
[tr. Screech (1987)]