As nought good endures beneath the skies,
So ill endures no more.

[Come cosa buona non si trova
Che duri sempre, così ancor né ria.]

Ludovico Ariosto (1474-1533) Italian poet

Orlando Furioso, Canto 37, st. 7 (1532) [tr. Rose (1831)]
    (Source)

Alt trans.: "For learn this truth, by just experience found, / Nor good, nor ill has one eternal round." [tr. Hoole (1807), l. 51]