Specific theological teaching is a primary function of pastors and elders...


Taken from page 56:

The essence of the Elder’s office is found in teaching - ensuring the Word of God is well understood. Such a ministry of teaching would show itself in the commitment to that task among the members of one’s own congregation. Anyone serving as an elder should have a better-than-average grasp of the basics of the Gospel, as well as the great truths of scripture, especially those that are under assault in one’s own day. 

An Elder should also have a particularly solid grasp of those truths which distinguish his own congregation from others, (e.g., Baptism).