Let’s see. Suppose I took a trip to China and loved it so much I wanted to move there. In fact, I decide to actually become Chinese. So I pack up and move there and apply for citizenship. I learn to speak Chinese, learn to cook Chinese food, wear the current Chinese fashions, get my hair styled like the Chinese and even go so far as to get plastic surgery so I’ll look Oriental. So now am I Chinese?
Not according to my DNA. It verifies that on the inside I am a westerner, not oriental. I may look and act Chinese on the outside but who I am on the inside is the real me.
It is the same with our sin nature. We can do a lot of good things such as giving to charities, going to church, helping others. But doing those outward deeds won’t change who we are on the inside, which is a sinner. Just as doing all those things to become Chinese won’t change my DNA, trying to do good deeds won’t change my sinfulness, basically my spiritual DNA. Trying to clean up our own self is like trying to clean a floor with an oily rag. It won’t work. The Bible says all our good deeds are as filthy rags. Only God can change who we are on the inside.