Letters 92.27

But some say: “Only to the immortal gods is given virtue and the happy life; we can attain but the shadow, as it were, and semblance of such goods as theirs. We approach them, but we never reach them.” Reason, however, is a common attribute of both gods and men; in the gods it is already perfected, in us it is capable of being perfected.

Seneca, Letters to Lucilius 92.27, translated by Richard Mott Gummere