Who can hope to be safe? who sufficiently cautious? Guard himself as he may, every moment's an ambush.

The lines express a bleak, vigilant view of human life: absolute security is impossible, because danger (whether literal violence, political reversal, illness, or moral temptation) can arise without warning. The rhetorical questions underscore the futility of trying to control every contingency—however carefully one “guards” oneself, time itself is hostile and unpredictable. In Horatian terms, this can be read as a reminder of life’s fragility and the limits of prudence, nudging the reader toward humility about planning and a sober awareness of fortune’s volatility. It also resonates with Roman experience of sudden political and social upheaval, where safety could be illusory.