Ministers in the Church of God have authority over Church members. God has given the ministry that authority. By ministry, I include top human leaders of fellowships, apostles, evangelists, pastors, down to local elders.
God commands that we obey them and submit to them (Hebrews 13:7, 17, 1 Thessalonians 5:12-13), and so we should, unless there is a biblical reason not to. We obey ministers because God commands us, but also to learn the lessons of government and teamwork we will live by in the Kingdom of God forever.
We are to obey those who have the rule over us. That means we obey the top leader of the Church of God organization we are a member of or regularly attend, whether that leader calls himself a pastor general, a president, an apostle, a prophet, a presiding evangelist, or some other title - it doesn't matter, the authority is there just the same. We are also to obey the pastor of the local congregation we are a member of.
There are two limitations on the authority of the ministry. One is well known and almost universally acknowledged in the Church of God, but one is not.
Ministers do not have the authority to make us sin. In other words, God's commandments come first. If a minister or a leader of the fellowship we attend commands us to do something that is a violation of God's word, the Bible, we are to obey God rather than man. A clear example is if a minister tells us to lie. God commands us not to lie (Exodus 20:16, Deuteronomy 5:20, Colossians 3:9, Revelation 21:8). We are to learn to be like God who cannot lie (Titus 1:2, Hebrews 6:18).
Sometimes a situation may come up where a minister's command may seem to come into possible conflict with a principle in God's word, but we aren't sure. Suppose a minister told me to not accept a certain job. Perhaps I feel he doesn't have a good reason for telling me that. God commands that we support our families (1 Timothy 5:8). I might feel that I need this job to fulfill the spirit of this biblical law. Yet, I think, perhaps there is another way to provide for my family, though it doesn't seem so. In this case, I need to pray about the matter and seek God's will.
In cases like this, it is helpful to understand, from the Bible, the purpose of a minister's authority. It is not so the minister can be like our parents and we like children so he can micro-manage our lives, but so the minister can help us in our relationship with God and with the brethren. "And He Himself gave some to be apostles, some prophets, some evangelists, and some pastors and teachers, for the equipping of the saints for the work of ministry, for the edifying of the body of Christ, till we all come to the unity of the faith and of the knowledge of the Son of God, to a perfect man, to the measure of the stature of the fullness of Christ; that we should no longer be children, tossed to and fro and carried about with every wind of doctrine, by the trickery of men, in the cunning craftiness of deceitful plotting, but, speaking the truth in love, may grow up in all things into Him who is the head - Christ - from whom the whole body, joined and knit together by what every joint supplies, according to the effective working by which every part does its share, causes growth of the body for the edifying of itself in love" (Ephesians 4:11-16). "Therefore I write these things being absent, lest being present I should use sharpness, according to the authority which the Lord has given me for edification and not for destruction" (2 Corinthians 13:10). "Moreover if your brother sins against you, go and tell him his fault between you and him alone. If he hears you, you have gained your brother. But if he will not hear, take with you one or two more, that by the mouth of two or three witnesses every word may be established. And if he refuses to hear them, tell it to the church. But if he refuses even to hear the church, let him be to you like a heathen and a tax collector. Assuredly, I say to you, whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven" (Matthew 18:15-18). See also Acts 6:1-6 and 1 Corinthians 5:1-5, 9-13.
In other words, God gave ministers authority over the organized work of the Church. This includes teaching doctrine, judging disputes between members, providing for the poor in the Church, disciplining members for serious and open sin, counseling, preaching the gospel to the world, and the like.
There is another limit on ministerial authority that is not so well acknowledged, but it is also important. Ministers and Church of God leaders do not have authority over what we believe. They have no authority over our faith. "Not that we have dominion over your faith, but are fellow workers for your joy; for by faith you stand" (2 Corinthians 1:24).
Faith must be towards God, not God's ministers (Hebrews 6:1). How does that work? We should read and study our Bibles and believe what God says, directly. When we read the Bible, God is speaking to us, and we are to believe Him. We should only believe the minister as he teaches according to the Bible, not contrary to the Bible.
Does God ever speak through a minister? Of course. Often God will inspire a minister to give us the teachings we need. We pray for God to do this before services, with the man giving the opening prayer asking God to inspire the speaking. But there is a difference. Ministers can make mistakes - God allows that. One minute a minister can tell us something very helpful and true, which God inspired him to say. The very next minute he may make a mistake and tell us something wrong because he is human and because God allows it. That's just the way it is.
How can we know which? By being familiar with the Bible. God wants us to know the Bible and live by it. And as we believe and obey God, God helps us understand by His Spirit.
The difference between God speaking through the Bible and speaking through the ministry is that the Bible is infallible, a minister is not.
Christ is indeed head of the Church, but He allows the Church to make mistakes. Look at the messages to the seven Churches in Revelation to see some of the mistakes they made, though Christ is their head (Revelation, chapters one, two, and three).
We must believe the Bible more than the Church and the ministry or we are making an idol out of the Church and the ministry. God and His word come first, the Church and the ministry second.
Yet the ministry has authority over the organized work of the Church, and that includes teaching doctrine, so if we disagree with the Church on a point of doctrine because we believe God more than man, we must refrain from criticizing and contradicting the Church and ministry in conversation with other brethren. Believe God and wait for Him to correct the error.
We can offer correction to a minister in private in a respectful way, if we think it will be helpful and if the minister is willing to listen. That kind of "correction" of someone above us in authority is approved by God in the Bible because it comes in the form of respectful and loving suggestion, counsel, and advice, as the servants of Naaman corrected their master (2 Kings 5:11-14). But we should not try to correct the situation in the Church by contradicting the ministry in front of other brethren, unless it is something so major that it is absolutely foundational to our faith, something worth leaving an organization over.
So we need to recognize that ministers and the Church have authority, but we need to know the limits of that authority. We need to believe and obey God first, yet respect and love the ministry even when they make human mistakes, and respect and support the lawful authority God has given them, obeying the Church as long as that obedience does not bring us into conflict with God's law and instruction in the Bible.
Here are links to related chapters or sections in Preaching the Gospel:
Should Each Member Promote His Own Opinion?, Chapter 6
Chapter 6 - Obtaining God's Help -- Practicing What We Preach
Chapter 9 - Repentance