Ecclesiastes 6:12
"For who knoweth what is good for man in this life, all the days of his vain life which he spendeth as a shadow? for who can tell a man what shall be after him under the sun?"
Cross References (ranked by relevance)
Whereas ye know not what shall be on the morrow. For what is your life? It is even a vapour, that appeareth for a little time, and then vanisheth away.
He cometh forth like a flower, and is cut down: he fleeth also as a shadow, and continueth not.
Wherefore I perceive that there is nothing better, than that a man should rejoice in his own works; for that is his portion: for who shall bring him to see what shall be after him?
Man is like to vanity: his days are as a shadow that passeth away.
(For we are but of yesterday, and know nothing, because our days upon earth are a shadow:)
For he knoweth not that which shall be: for who can tell him when it shall be?
For we are strangers before thee, and sojourners, as were all our fathers: our days on the earth are as a shadow, and there is none abiding.
But it shall not be well with the wicked, neither shall he prolong his days, which are as a shadow; because he feareth not before God.
My days are like a shadow that declineth; and I am withered like grass.
His sons come to honour, and he knoweth it not; and they are brought low, but he perceiveth it not of them.
I sought in mine heart to give myself unto wine, yet acquainting mine heart with wisdom; and to lay hold on folly, till I might see what was that good for the sons of men, which they should do under the heaven all the days of their life.
Also their love, and their hatred, and their envy, is now perished; neither have they any more a portion for ever in any thing that is done under the sun.
As for me, I will behold thy face in righteousness: I shall be satisfied, when I awake, with thy likeness.
I am gone like the shadow when it declineth: I am tossed up and down as the locust.
Let us hear the conclusion of the whole matter: Fear God, and keep his commandments: for this is the whole duty of man.
There be many that say, Who will shew us any good? LORD, lift thou up the light of thy countenance upon us.
He hath shewed thee, O man, what is good; and what doth the LORD require of thee, but to do justly, and to love mercy, and to walk humbly with thy God?
Remember how short my time is: wherefore hast thou made all men in vain?
He shall choose our inheritance for us, the excellency of Jacob whom he loved. Selah.
The LORD is the portion of mine inheritance and of my cup: thou maintainest my lot.