Scripture repeatedly compares spiritual immaturity to infancy or subsistence on milk (Hebrews 5:12-14). We are called to grow up into Christ. Here's a wonderful article written by John Ortberg that you will find inspiring. After you have read it, let us know what you are doing to grow up into Christ.
Spiritual growth is not complicated. It’s measured by love. If someone asks how my spiritual life is going, the first diagnostic question is: Am I growing more or less loving these days? Click here for the answer