1) How congregational-authority and elder-authority go together. 

            - Jesus gives all believers, when gathered as congregations, the authority of the keys.

            - The congregation gets to exercise that authority together with and under the leadership of the elders.

2) How exactly does a church employ or exercise the keys? Through the ordinances.

            - If baptism is the “initiating oath-sign” of the new covenant community, the Lord’s Supper is the “renewing oath-sign.”

            - If baptism binds one to many, the Lord’s Supper binds many into one.

            - In other words, baptism and the Lord’s Supper make the church visible