They are not to act out their own feelings or opinions. They are simply to declare what Christ has said. Unto no man or body of men has Christ delegated authority to legislate on doctrine. No authority other than God Himself should pass laws which can bind or loose the consciences of men. The disciples were to teach what Christ had taught-that which He had spoken, not only in person, but through prophets and apostles, included.
Human teaching is shut out.
There is no place for tradition, for man's theories and conclusions, or for church legislation. No laws ordained by ecclesiastical authority are included in the commission. None of these are Christ's servants to teach. When the Word of God is mixed with faith, it will profit the receiver. But when it is mixed with human opinions and decrees, it becomes like the bread which Ezekiel was commanded to eat.