Here John MacArthur answers a great question that many people have
While I agree with him that an Arminian can be a Christian, even thought their understanding strays from orthodox Christianity. We tend to define the Gospel so narrowly and leave out sanctification and our glorification as part of the Gospel (and “good news” it is). Arminianism truncates the Gospel and that concerns me greatly. I want people to understand and embrace the fullness of the Gospel message. I believe that it is in this sense that Spurgeon was right in saying “Calvinism is the Gospel.”
We must understand that while a brother may disagree with this, that they do so to the harm of their spiritual life. There are many doctrines and beliefs in ministry that are essential because they relate to making disciples (disciplemaking) in the church , ecclesiology, and our sanctification. 1 Peter 1:3 states: …seeing that His divine power has granted to us everything pertaining to life and godliness, through the true knowledge of Him who called us by His own glory and excellence. I don’t think we should minmize things that pertain to life and godliness.
I think a solution would be to understand that every propositional truth in the Bible is essential to our understanding of God, while they may be at different levels of importance at a time and place. It seems that today that we want to minimize the number of truths that we call essential. Essential for what? It is not that we understand everything about a doctrine, but the concern I have is that when we deny any orthodox doctrine as essential, we do harm to our spiritual lives and to the the church as whole. It is almost like we are telling God that we don’t need parts of the Bible. While I would make sure a new believer understood the doctrine of the Trinity before I delved into helping them understand their spiritual gifts, I am of the conclusion now that I should not call spiritual gifts unessential. Yes it is true we need to be able to do Spiritual and Theological Triage (prioritizing of needed truth at a specific time and place), but that is far different that saying something is non-essential. Christians don’t want to stand for a minimized truth, but be able to develop unity with other Christians across theological boundaries (without moving those boundaries).
It is a popular to quote “In essentials unity, in non-essentials charity, and in everything love.” The problem comes when we try to minimize the essentials and call the rest non-essentials just so that we can get along. Because of this our ministry become shallow (and many times man-centered) because truth is based on what people agree on (which is a terrible understanding of truth). I agree with that statement, but we need to understand that the non-essentials are applications and personal convictions about what we eat, movies we can go to, whether we should have a TV in our homes, etc.. Romans 14 gives a great account of this. I will unpack more of my ideas on this topic later.