When times are good, be happy; but when times are bad, consider this: God has made the one as well as the other. Therefore, no one can discover anything about their future. Ecclesiastes 7:14

The following poem by Alexander Pope fleshes this thought out in these lines from one of his essays.

HEAVEN from all creatures hides the book of fate,
All but the page prescrib’d, their present state:
From brutes what men, from men what spirits know:
Or who could suffer being here below?
The lamb thy riot dooms to bleed to-day,
Had he thy reason, would he skip and play?
Pleas’d to the last, he crops the flow’ry food,
And licks the hand just rais’d to shed his blood.
Oh blindness to the future! kindly giv’n,
That each may fill the circle mark’d by Heav’n:
Who sees with equal eye, as God of all,
A hero perish, or a sparrow fall.
Atoms or systems into ruin hurl’d,
And now a bubble burst, and now a world.
Hope humbly then; with trembling pinions soar;
Wait the great teacher death, and God adore.
What future bliss, he gives not thee to know,
But gives that hope to be thy blessing now.
Hope springs eternal in the human breast:
Man never is, but always to be blest. So, Pope's conclusion of the essay is this --- "All nature is but art, unknown to thee; All chance, direction, which tho canst not see;  All discord, harmon not understood;  All partial evil, universal good;   And spite of pride, in erring reason's spite,  One truth is clear, Whatever is, is right."