“There is nothing that enters a man from outside which can defile him; but the things which come out of him, those are the things that defile a man.” (Mark 7:15)
When I was in college the popular thinking in academic circles was that until a child was born it was all about heredity and after a child was born all that mattered was environment. The political philosophy of people like Lynden Baines Johnson and his Great Society was that if we improve the environment of a person we will solve their problems.
As a social worker that didn’t work for me. For example, I once found a marvelous foster home for a 12 year old boy from the ghetto of a large city. An older couple had a very large farm and they wanted to share it with an adopted son. All the way to the farm I explained to him what an opportunity this was for him. By the time I arrived back to my office I had a message from the perspective foster mother telling me to pick up “this little thief.” He had stolen from the purses of ladies who had come to play bridge with her.
Changing the young man’s environment did not change him from the inside out or in his heart. In the passage from which the verse above is taken Jesus went on to explain that the issues of life that determine the character of a human being are not a matter of outside in influences. Rather they are the inside out influences of the heart.
That is why the prayers of discerning hearts are: “Search me Oh God and know my heart.” And “Create in me a clean heart, O God.” (Psalm 139: 23; Psalm 51: 10)