Paul begins chapter 14 of Romans by challenging believers not to quarrel over differences of opinions. The word opinions has been translated as doubtful things, disputable matters or even gray areas. These are issues where the bible has not given clear instruction for believers.
This conflict over differences in opinions, Paul says, comes from conflict between those who are stronger and weaker in faith. Weakness in the body can come from a variety of causes. It can come from being immature or ignorant. It can come from bad teaching, and it can also come from lack of exercise.
An important note here is that the weakness described suggests it's not permanent, but it's a lack of resources for strength. This indicates that with the proper resources, weakness can be overcome.
Whatever the reason for someone being weak in their faith, we are instructed to welcome them. Spiritual maturity is not a requirement for fellowship. If weaker believers are not received and encouraged by those who are stronger in their faith, how are they to grow?
Paul gives us two important principles to maintain fellowship in the face of conflict.
1. Receive the weaker brother (or sister)
Welcome and do not quarrel. We are to welcome as God has welcomed. If God has welcomed someone into the family, we must not exclude that person, because we are acting as body and as representatives of Christ. No matter where believers are in their faith journey, we all started out new and none of us are completed yet. Falsely telling someone that they are not welcomed or making them feel excluded misrepresents the heart of God.
2. Do not despise or judge each other over differences
We must not allow disagreement to divide us. While we may have disagreements, we should recognize that there is a progressive maturity that will happen naturally as God leads his children. Let's not quarrel or separate over matters that are not central to our faith and the person of Jesus Christ and his saving work.
Paul encourages all believers to not be satisfied with opinions and taking sides, but instead to become fully convinced. That is, Paul is challenging all of us to search out the scriptures to see what God has said, to pray and seek the Holy Spirit, and to listen to the wisdom of other believers. The purpose in this is not to justify our opinions, but to be open to the truth and the guiding of God.
Whatever we do, we must be fully convinced in our own minds that it honors The Lord.