It's very true, and is what as the law of Tao or flow. When you give out anything, it creates an energetic vacuum in your life into which the out flowed thing flows back to you, but flows back multiplied. Give money, get money back multiplied (also known as 'when things get tight, give'). Give love, get love back multiplied. Help someone with something you are struggling with, and that help will come back to your life as help in something you need help with. Give advice, receive back advice on something you need to know. And if you don't know how to do this, then you can visualise yourself doing the thing in question, then you will attract the scenarios where you do, and the opportunities to give out. Giving becomes its own reward in this way.