But doctors are lucky: the sun shines on their successes and the earth hides their failures.

[Mais ils ont cet heur, que le soleil esclaire leur succez, & la terre cache leur faute.]

Michel de Montaigne (1533–1592) French essayist

Essays, Book 2, ch. 37 (2.37), “Of the Resemblance of Children to their Fathers [De la ressemblance des enfans aux peres]” (1579–1580) [tr. Screech (1987)]
    (Source)

The phrase is not original to Montaigne, but he popularized it. The above is how this was rendered in the 1st (1580) edition; with the 2nd (1588) edition onward, he gave credit to one Nicocles (adding "selon Nicocles [according to Nicocles]" after the comma/colon break.

The fragment by Nicocles [Νικοκλῆς] (it is unclear who of that name is referenced) can be found in The Collection of the Monks Antonius and Maximus [Sententiarum sive Capitum, Theologicorum praecipue, ex Sacris et Profanis Libris, Tomi Tres], ch. 146, usually included at the end of Stobaeus.

See also Wright (1930).

(Source (French)). Other translations:

[Physitions] have this happe, That the Sunne doth manifest their successe, and the earth doth cover their fault.
[tr. Florio (1603)]

But physicians have this advantage, "That the sun gives light to their success, and teh earth covers their miscarriages."
[tr. Cotton (1686)]

But they [physicians] have this advantage, that the sun gives light to their success and the earth covers their failures.
[tr. Cotton/Hazlitt (1877)]

But [doctors] have this advantage, that the sun lights up their successes and the earth hides their failures.
[tr. Ives (1925)]

But [physicians] have this good luck: that the sun shines on their successes, and the earth covers their failures.
[tr. Zeitlin (1934)]

But [doctors] have this luck, that the sun shines on their successes, and the earth hides their failures.
[tr. Frame (1943)]