Pry not, the morrow’s chance to learn:
Set down to gain whatever turn
The wheel may take.
 
[Quid sit futurum cras, fuge quaerere, et
quem fors dierum cumque dabit, lucro
adpone.]

Horace (65-8 BC) Roman poet and satirist [Quintus Horacius Flaccus]

Odes [Carmina], Book 1, # 9, l. 13ff (1.9.13-15) (23 BC) [tr. Gladstone (1894)]
    (Source)

To Thaliarchus.

(Source (Latin)). Alternate translations:

Upon to Morrow reckon not,
Then if it comes 'tis clearly got.
[Fanshaw (1666)]

All Cares, and Fears are fond and vain,
Fly vexing thoughts of dark to-morrow;
What Chance scores up, count perfect gain,
And banish business, banish sorrow.
[tr. Creech (1684)]

To-morrow and her works defy,
Lay hold upon the present hour,
And snatch the pleasures passing by,
To put them out of fortune's power:
[tr. Dryden (c. 1685)]

O, ask not what the morn will bring,
But count as gain each day that chance
May give you.
[tr. Conington (1872)]

Avoid inquiring what may happen to-morrow; and whatever day fortune shall bestow on you, score it up for gain.
[tr. Smart/Buckley (1853)]

Let not to-morrow's change or chance
Perplex thee, but as gain
Count each new day!
[tr. Martin (1864)]

Shun to seek what is hid in the womb of the morrow;
Count the lot of each day as clear gain in life’s ledger.
[tr. Bulwer-Lytton (1870)]

What brings to-morrow care not to ask, and what
Fortune each day may bring, set it down as gain.
[tr. Phelps (1897)]

What is to be to-morrow do not ask: appraise
As gain the course of days Fortune will yield.
[tr. Garnsey (1907)]

What next morn's sun may bring, forbear to ask;
But count each day that comes by gift of chance
So much to the good.
[tr. Marshall (1908)]

Cease to ask what the morrow will bring forth, and set down as gain each day that Fortune grants!
[tr. Bennett (Loeb) (1912)]

Ask not the morrow's good or ill;
Reckon it gain however chance
May shape each day.
[tr. Mills (1924)]

Try not to guess what lies in the future, but
As Fortune deals days enter them into your
Life's book as windfalls, credit items,
Gratefully.
[tr. Michie (1963)]

Stop wondering after tomorrow: take
Day by day the days you’re granted.
[tr. Raffel (1983)]

Cease to ask what tomorrow may bring
and count as gain whatever Fortune grants you today.
[tr. Alexander (1999)]

Don’t ask what tomorrow brings, call them your gain
whatever days Fortune gives.
[tr. Kline (2015)]

Leave off asking what tomorrow will bring, and
whatever days fortune will give, count them
as profit.
[tr. Wikisource (2021)]