The Apostle Paul answered your question/dilemma in Philippians 3:
15 Let us therefore, as many as are perfect, have this attitude; and if in anything you have a different attitude, God will reveal that also to you; 16 however, let us keep living by that same standard to which we have attained.
Please note Paul’s words carefully. He does not say, if any have a different attitude, assembly-authority [which is a more accurate translation of the Greek than,’church-authority’] will resolve the problem. He says, “God will reveal that also to you.”
Two points. God WILL reveal His truths to us if we seek them. This promise is made repeatedly in Scripture. However, (point Two), some do not desire God’s truth. They are too mired in one error or another to wholly and prayerfully submit to God’s guidance. That doesn’t invalidate Paul’s prescription for acquiring wisdom and insights; it simply explains why errors persist.
So how is one person to know when he is in error? Up until 1930ish... All Christian denominations scrripturally showed and believed that artificial birth control was sinful... Then the episcopalians caved and said it was ok... Then most followed suit. So the question follows... We’re Christians properly interpreting the scriptures for the first 2000 years? Or have they only been properly interpreted just he last 100?