The Law of Sowing and Reaping has not been repealed. It is still operating. Today we call a person who continually rescues another person a codependent. He continues to be loved, pampered, and treated nicely. Establishing boundaries helps codependent people stop interrupting the Law of Sowing and Reaping in their loved one's life.
Boundaries force the person who is doing the sowing to also do the reaping.
It doesn't help just to confront the irresponsible person. I have tried many times to let him know what I think about his behavior and that he needs to change. In reality, my client is only nagging Jack. Jack will not feel the need to change because his behavior is not causing him any pain. If Jack is wise, confrontation might change his behavior.