I’ve done some more reading in William MacDonald’s Believer’s Bible Commentary and came across another very thought-provoking section on Ephesians 4:14. As MacDonald points out, it is very important that we have solid teaching and leadership in the Church or it will suffer the consequences:
When the gifts [given to the Church] operate in their God-appointed manner, and the saints are active in service for the Lord, three dangers are avoided—immaturity, instability, and gullibility.
Immaturity. Believers who never become involved in aggressive service for Christ never emerge from being spiritual children. They are undeveloped through lack of exercise. It was to such that the writer to the Hebrews said, “For though by this time you ought to be teachers, you need someone to teach you again
--.” (Heb. 5:12).
Instability. Another danger is spiritual fickleness. Immature Christians are susceptible to the grotesque novelties and fads of professional quacks. They become religious gypsies, moving to and fro from one appealing fantasy to another.
Gullibility. Most serious of all is the danger of deception. Those who are babes are unskillful in the word of righteousness, their senses are not exercised to discern between good and evil (Heb. 5:13, 14). They inevitably meet some false cultist who impresses them by his zeal and apparent sincerity. Because he uses religious words, they think he must be a true Christian. If they had studied the Bible for themselves, they would be able to see through his deceitful juggling of words. But now they are carried about by his wind of doctrine and led by unprincipled cunning into a form of systematized error.