References: Ephesians 4
One of the problems Paul addressed in Ephesians is still a problem today: spiritual immaturity. It isn't enough to be born into the family of God, we have to grow up. Babies aren't meant to be babies forever, and spiritual babies shouldn't be abandoned to their own devices or left unprotected. Those who come to Christ must grow in Him in the Word, so they too can do the work God has saved them for. We'll see the need for telling the truth in love, which means we need to know the truth and be committed to it. And since the Body only functions if all the parts are doing their job, we need to do our part of the ministry.