God gave His children the Holy Spirit to guide us with wisdom and understanding. Pastors and teachers are no better than any saint (which, of course, describes everyone who is in Christ), though we must admit individuals yield to the Lord and gain understanding in proportion to that yielding.
Yes, Scripture and not any man, is the authority on what God has said and means. No pope nor Baptist preacher - none but the Lord.
I would say that some are called to certain works, such as pastor, preacher, evangelist, etc and are especially gifted toward those works by the Holy Spirit. It does not mean, however, that they are immune from sin, as we can all attest to.
Amen.