That brothers and sisters will inevitably disagree is firmly attached to the humanity of mankind. As Paul sets out in Romans we are all sinners (3:23). We sin morally, that is we fail to always do everything correctly in light of God's perfection. We sin doctrinally, that is, try as we do the truth of God's revelation often escapes us. No one can say "I have never changed my mind" (except perhaps the hard hearted). Beyond that is the difficulty of obeying the "greatest command" and as Jesus said "praying for those who persecute us."
Discussions regarding "doctrinal" issues existed in the NT (Acts 15) and persist today. If it were not for "doctrinal" failings Paul would have had no reason to write any of his Epistles. Paul, Peter, John and James wrote in order to remedy difficulties brethren had with moral and doctrinal issues. We are no better than they.
The grace of God is here for all of honest heart no matter how far afield they may fly either morally or doctrinally. If the heart is good before God the grace of God is near. Foree