“A heart well prepared for adversity in bad times hopes, and in good times fears for a change in fortune.”

80:8
Sermons

The origin of this quote is often misattributed to Cicero; however, it is from Line 135-136 of Book 2, Satire 2 by Horace, "Quocirca vivite fortes, fortiaque adversis opponite pectora rebus." The English translation that most closely matches the one misrepresented as Cicero's is from a collection of Horace's prose written by E. C. Wickham, "So live, my boys, as brave men; and if fortune is adverse, front its blows with brave hearts."
Misattributed

Lyrics

Book II, Satire II, Line 135-136 (trans. E. C. Wickham)
Satires (c. 35 BC and 30 BC)

Source: The Prince (1513), Ch. 3 (as translated by RM Adams). Variants [these can seem to generalize the circumstances in ways that the translation above does not.]: The Romans, foreseeing troubles, dealt with them at once, and, even to avoid a war, would not let them come to a head, for they knew that war is not to be avoided, but is only put off to the advantage of others.
There is no avoiding war; it can only be postponed to the advantage of others.
Context: The Romans never allowed a trouble spot to remain simply to avoid going to war over it, because they knew that wars don't just go away, they are only postponed to someone else's advantage. Therefore, they made war with Philip and Antiochus in Greece, in order not to have to fight them in Italy... They never went by that saying which you constantly hear from the wiseacres of our day, that time heals all things. They trusted rather their own character and prudence — knowing perfectly well that time contains the seeds of all things, good as well as bad.

Source: The Way of Kings

So don't worry if now your time is bad it's making you strong so nothing can effect you in future

Misattributed