The trouble with doing things to impress God is it forces you to keep coming up with more and better things to do for God. For instance, if you really want God to bless you, then maybe you can do more than the average person to earn more of His favor. Throughout history people have become monks, fasted, or endured masochistic pain as religious acts of devotion. Paul refers to this in verse 23 when he writes about “harsh treatment of the body.” Those kinds of acts may appear valuable, but the Bible says they are worthless.