The future you shall know when it has come; before then forget it.

The line counsels a disciplined humility toward what has not yet happened: the future is not an object of reliable knowledge, so anxiety and speculation are wasted effort. It implies a practical ethics of attention—deal with what is present and knowable, and let the future disclose itself in its own time. In Aeschylean terms, such advice also resonates with the limits placed on human foresight in a world governed by divine order and fate: mortals may receive omens or prophecies, but certainty arrives only when events become facts. The aphoristic tone makes it readily detachable from its dramatic setting, which helps explain its later life as a general maxim.