“Welcome those who are weak in faith, but not for the purpose of quarreling over opinions.” (Romans 14:1)
The meaning of “weak” here is not weakness in the depth of their belief but the extent to which their faith is tied to outward signs and practices. Paul being Paul would not tolerate someone who was wishy-washy as to whether he/she believed in Jesus as God’s son and sent to atone for our sins. . .