The key method Paul underscores as the means to the transformed life is by the "renewal of the mind." This means nothing more and nothing less than education. Serious education. In-depth education. Disciplined education in the things of God. It calls for a mastery of the Word of God. We need to be people whose lives have changed because our minds have changed.
True transformation comes by gaining a new understanding of God, ourselves, and the world. What we are after ultimately is to be conformed to the image of Christ. We are to be like Jesus, though not in the sense that we can ever gain deity. We are not god-men. But our humanity is to mirror and reflect the perfect humanity of Jesus. A tall order!
To be conformed to Jesus, we must first begin to think as Jesus did. We need the "mind of Christ." We need to value the things He values and despise the things He despises. We need to have the same priorities He has. We need to consider weighty the things He considers weighty.
That cannot happen without a mastery of His Word. The key to spiritual growth is in-depth Christian education that requires a serious level of sacrifice.
That is the call to excellence we have received. We are not to be like the rest of the world, content to live our lives with a superficial understanding of God. We are to grow dissatisfied with spiritual milk and hunger after spiritual meat.