Graduation is a time for new beginnings. It's proof that you've completed a portion of your education and it's time to move on to the next phase of your life. For some, this means going on to higher education, and leaving the comfort of the childhood home. For others, it will be time to move on into adulthood and begin providing for themselves and become a productive member of society. No longer do they need someone to spoon feed them because they've learned to feed themselves. As believers, we also need to graduate from being fed to feeding ourselves. When we attend church on Sunday mornings, this should be like "continuing education", a time to confirm what you believe and not so much the whole of your biblical education. If all you're getting is coming from your preacher, your missing out on a lot of the wisdom contained in the Word of God. God speaks to us through His Word. Don't you want to hear what He has to say?
You need milk, not solid food, for everyone who lives on milk is unskilled in the word of righteousness, since he is a child. But solid food is for the mature, for those who have their powers of discernment trained by constant practice to distinguish good from evil. Hebrews 5:12-14