You see, a good part of the work of the ministry is helping believers mature in Christ. This is at least for two important reasons: First, as this passage indicates there is a need to ground believers in the truth of the Bible, not the fanciful teaching of some, such as the "Prosperity Gospel" - the notion that God wants you rich and important in the eyes of the world. Or the teaching that God is really only interested in those who hide away in monasteries and have nothing to do with the world around them. Or the teaching that you can get saved and then go out and live any way your flesh wants to live! The work of the ministry is teaching the truth to warn against false teaching.
The second important reason for this work is to bring Christians into a mature walk. That is, their lifestyle will show the depth of their devotion to Christ. They won't be living self-centered, but instead, they will be living Christ-centered. They won't be pessimistic about their "lot in life," but rather, they will learn to rejoice in all things and live contented lives knowing that God has a plan for everything He allows to happen to them.
Can you see mature growth in believers around you? Can they see mature growth in you?