That way, I'd know what I was shooting for in my own maturing, and would also be able to point out the target for those I was discipling. So I looked up every place in the Bible where adults were described - fathers, mothers, parents, elders, leaders, pastors, etc. A spiritual adult is someone who takes care of spiritual babies. This is clearly seen as one of the major jobs of parents in Old Testament times. Because this characteristic was sadly lacking in the Hebrew Christians, Paul blasted them with both barrels in Hebrews.
Input is fine for babies, but output is the goal for adults.
A grownup isn't afraid to put a little teeth into his or her teaching. I do it with my kids, and my dada did it with me. One of the reasons the Body of Christ today is so full of spiritual wimps is because it's so full of wimpy spiritual parents. They can discipline, but they aren't tyrants. A grown up Christian knows the difference between the loving hand of a father or a mother, and the vindictive, self-seeking hand of a tormentor.