The pursuit of excellence is a noble thing. We are all fans of “becoming your best self.” Christians want the spiritual version of that: Be the best person in Christ that you can be.
The problem is that this type of catchphrase blurs the line between being biblically perfect and just plain being a perfectionist. There is a big difference.
We all want to do well, to be excellent, at the top of our game; but perfectionism is compelled by fear and pride. It is a compulsion to succeed without even the tiniest error, and it can bring us to ruin by neglecting other, needful things or by paralyzing us with fear of failure. As Christians, we are sometimes conditioned to this perfectionism by being taught that this is how we please God or other people. Fear of judgment in the absence of perfection is a cruel and relentless taskmaster that can, if we let it, rule over us night and day.
When Jesus spoke the words, “You therefore must be perfect, as your heavenly Father is perfect” (Matthew 5:48, ESV), he had just prior to that told us what he meant. He emphasized that he came to fulfill that demand for perfection on our behalf, and he knew we could not be perfect by our own efforts. Scripture is filled with wildly imperfect people who became great heroes of the faith. Jesus wants us to strive imperfectly to do our best and to depend upon him. There isn’t one human being who has ever lived who was perfect in themselves. Every one of us has failed, time and again. It is the redemption of Christ’s death on the cross which makes us perfect; it's all him, every time. Our perfection is not in our control.
It is when we take our eyes off our ourselves and our efforts to do everything right, that we find peace, perfection and freedom. Know this: your past, present and future are covered by the blood of Jesus Christ. You have no need to perform before him because he already knows how imperfect you are.
Scripture says to “let us also lay aside every weight, and sin which clings so closely” (Hebrews 12:1). God desires that we lay down our perfectionism. He wants us to live with childlike authenticity and dependence upon him. He is most pleased when we bring our real and imperfect selves to him.