NO ONE CAN BE PERFECT from morning to night. But that hasn't stopped people from trying.
Look as far back as Biblical history, and you will find that human perfectionism was just as much a preoccupation then as it is now. There's the story of Mary and her overly conscientious sister, Martha, who did everything in her power to make Jesus feel well-received in her home. And the rich young man who, having fulfilled the letter of the theological law, assumed that he was thereby approximating a more perfect life. They and many others appear to have expected a human brand of perfection of themselves—and possibly of others. And yet, Jesus didn't encourage these endeavors. Instead, he urged people to let go of such human striving in favor of a more spiritual focus.
If the same man who admonished followers "Be ye therefore perfect, even as your Father which is in heaven is perfect" Matt. 5:48. didn't advocate the pursuit of human perfection, then what was he encouraging? It can help to begin by looking at the Greek word for perfect, teleios, which has been translated as complete, whole, and spiritually mature—words that contrast starkly with the Pharisaical righteousness and rigid codes of conduct that so often become associated with the human version of perfection.