5 ideas
"Cast your bread upon the waters, for you will find it after many days" says that goods sent away without a visible or immediate return can come back later. Returns on generosity and investment are delayed and hard to trace, so waiting to see the payoff before letting go means never acting.
"Give a portion to seven, and also to eight, for you know not what evil shall be upon the earth." Because you cannot predict which calamity will come, you should spread your resources across many holders rather than concentrate them. When forecasting fails, dividing your holdings is the fitting response, and the uncertainty itself is the reason for it.
"He who observes the wind will not sow, and he who regards the clouds will not reap." Conditions are never clearly favorable, so demanding certainty before acting means the season passes with nothing planted. The cost of watching too closely for the right moment is often greater than the risk of acting at the wrong one.
"In the morning sow your seed, and in the evening withhold not your hand, for you know not which shall prosper, this or that, or whether both alike shall be good." Here you spread effort over different times as well as different ventures. Since you cannot tell ahead of time which effort will succeed, you keep up steady action across times of day and leave the outcome open, and sometimes every effort succeeds.
The chapter says that people do not know the way of the wind, or how bones grow in the womb, and in the same way they cannot know the works of God. Admitting this ignorance becomes the basis for practical rules like acting, spreading effort, and not waiting.