How to pick right from wrong?

A young professional was once offered a large sum of easy money for a job that made him somewhat uneasy. It wasn’t quite illegal but struck him as unethical. He was confused whether he should undertake the job or not. He requested the client to give him a day to decide. That night, he went home and told his mother about the terms and conditions of the contract and the big money that was involved. His mother was totally an illiterate. After listening to him for two hours she said, “Son, I don’t understand anything of what you just said. All I can say is one thing – that every morning when I come into your room, I find you fast asleep. I have a very hard time waking you up. I would hate to wlk into your room one day and find you awake. The final decision is yours. You decide.” With these words the mother left the room. The young man said to himself, “I got my answer”.