This is loyalty in ministry taken too far. If only you stopped at be subject to authority, if you are not having the same conviction on issues, leave. But going to the extent of saying "if you listen to the voice of God, you will be useless" and it stops there is misleading.

The difference between substance and delivery is evident here. Much as he is saying the truth, the method of delivery is too unfriendly and abusive. There must be a structure in a church to guide messages from the pulpit and an assistant pastor must respect such structure. If a subordinate does not want to do that, let him go and start his own ministry