There is a biblical prescription for local church polity. Jesus Christ is the Head of the Church. Under His headship each local church is elder-led. This elder leadership is congregationally affirmed. Those who have been affirmed as leaders have biblically-granted authority, responsibility, and accountability.
Those who function as elders are biblically-qualified males who are affirmed by the congregation. The vocational and lay elders function together as the elders of the church. The elders have the responsibility and the authority to lead the congregation in discerning the mind of Christ for all the decisions of the church and shepherding the church in those decisions.
The congregation, as the temple of the Holy Spirit, affirms the leadership of the elders. There are decisions in which the congregants contribute in helping the elders find/discern the mind of Christ.
As an association of autonomous churches, our polity will seek to reflect the biblical model for the church. Trustees must be members in good standing of an association church and recommended by their church. Area Association Trustees must also be biblically-qualified for eldering and chosen by their area association.