Romans 14

v1-12: As a general rule you are to be zealous "in those things on which you and all the people of God are agreed" and not "quarrel about matters that are disputable." We are to receive those who we disagree with on disputable matters into our "company, conversations, and fellowship... and encourage [them] in every possible way," because God has received them, and "we are reflecting badly on him if we reject those whom he has received."

v13-23: We must seek both mutual peace and mutual edification, with mutual peace the way to mutual edification, because "we cannot edify one another while we are quarrelling and competing one another."  We all need to be edified and built up in the faith.  "No one is so strong that they do not need to be further built up; no one is so weak that they cannot build others up; and when we build others up, we also benefit ourselves."