Ecclesiastes 11:5-8

As thou knowest not what is the way of the wind, nor how the bones do grow in the womb of her that is with child; even so thou knowest not the work of God who doeth all. In the morning sow thy seed, and in the evening withhold not thy hand; for thou knowest not which shall prosper, whether this or that, or whether they both shall be alike good. Truly the light is sweet, and a pleasant thing it is for the eyes to behold the sun. Yea, if a man live many years, let him rejoice in them all; but let him remember the days of darkness, for they shall be many. All that cometh is vanity.