Simonides, fragment 521 (tr. Douglas E. Gerber):
You are man: then never say what will happen tomorrow, nor, when you see a prosperous man, how long he will prosper; for not even the movement of a long-winged fly is so swift.
The same (tr. Charles Segal):
Being human never say what will happen tomorrow nor how long a happy man will remain so. For not even of a long-winged fly is the change so swift.
The same (tr. M.L. West):
As you are mortal, don't ever affirm what tomorrow will bring,
or how long the man that you see in good fortune will keep it:
not even the wing-spreading house-fly
changes perch so fast.
The same (tr. Willis Barnstone):
If you are a simple mortal, do not speak
of tomorrow or how long this man may be
among the happy, for change comes suddenly
like the shifting flight of a dragonfly.
ἄνθρωπος ἐὼν μή ποτε φάσῃς ὅ τι γίνεται αὔριον,
μηδ᾿ ἄνδρα ἰδὼν ὄλβιον ὅσσον χρόνον ἔσσεται·
ὠκεῖα γὰρ οὐδὲ τανυπτερύγου μυίας
οὕτως ἁ μετάστασις.