Sowing and reaping are universal laws of nature because God set them up to be universal laws of nature. These laws work in all things. What ever is sown is ultimately what is reaped. Scriptures declare it! Here is just one.
Gal 6:7-9
7 Be not deceived; God is not mocked: for whatsoever a man soweth, that shall he also reap…for in due season we shall reap, if we faint not (KJV)
This Scripture principle applies to the sowing of finances as well to sowing seed on a farm…