Happy the man, and happy he alone,
He, who can call today his own:
He, who, secure within, can say
Tomorrow, do thy worst, for l have lived today.
Be fair, or foul, or rain, or shine,
The joys l have possest, in spite of fate, are mine.
Not Heav’n itself upon the past has power;
But what has been, has been, and l have had my hour.https://www.bartleby.com/204/190.html Translations with less power: https://newepicurean.com/quintus-horatius-flaccus-horace-ode-3-29/
Horace, from the 29th Ode of the third book.