There are certain people who so ardently and so passionately desire a thing, that from dread of losing it they leave nothing undone to make them lose it.

[Il y a de certaines gens qui veulent si ardemment et si déterminément une certaine chose, que de peur de la manquer, ils n’oublient rien de ce qu’il faut faire pour la manquer.]

Jean de La Bruyère (1645-1696) French essayist, moralist

The Characters [Les Caractères], ch. 4 “Of the Heart [Du Coeur],” § 61 (4.61) (1688) [tr. Van Laun (1885)]
    (Source)

(Source (French)). Alternate translations:

There are those People, who so ardently and passionately desire a thing, that for fear they shall lose it, they leave nothing undone that may surely make 'em lose it.
[Bullord ed. (1696)]

There are certain People, who so ardently and passionately desire a thing, that out of fear of losing it, they leave nothing undone to make 'em lose it.
[Curll ed. (1713)]

Some so ardently and passionately desire a thing, that out of fear of losing it, they run into Measures which infallibly makes them lose it.
[Browne ed. (1752)]

There are some people who are so ardently and resolutely bent on gaining a certain thing that, for fear of losing it, they do everything that is likely to lose it for them.
[tr. Stewart (1970)]