Only a Difference of Opinion?

A difference of opinion concerning doctrine may take place between two equally sincere Christians. When this happens, should this difference be treated as a trifle? J. Gresham Machen explains:

[One] difference of opinion which can subsist in the midst of Christian fellowship is the difference of opinion about the mode of efficacy of the sacraments. That difference is indeed serious, and to deny its seriousness is a far greater error than to take the wrong side in the controversy itself. It is often said that the divided condition of Christendom is an evil, and so it is. But the evil consists in the existence of the errors which cause the divisions and not at all in the recognition of those errors when once they exist. It was a great calamity when at the ‘Marburg Conference’ between Luther and the representatives of the Swiss Reformation, Luther wrote on the table with regard to the Lord’s Supper, ‘This is my body,’ and said to Zwingli and Oecolampadius, ‘You have another spirit.’ That difference of opinion led to the breach between the Lutheran and the Reformed branches of the Church, and caused Protestantism to lose much of the ground that might otherwise have been gained. It was a great calamity indeed. But the calamity was due to the fact that Luther (as we believe) was wrong about the Lord’s Supper; and it would have been a far greater calamity if being wrong about the Supper he had represented the whole question as a trifling affair. Luther was wrong about the Supper, but not nearly so wrong as he would have been if, being wrong, he had said to his opponents: ‘Brethren, this matter is a trifle; and it makes really very little difference what a man thinks about the table of the Lord.’ Such indifferentism would have been far more deadly than all the divisions between the branches of the Church. A Luther who would have compromised with regard to the Lord’s Supper never would have said at the Diet of Worms, ‘Here I stand, I cannot do otherwise, God help me, Amen.’ Indifferentism about doctrine makes no heroes of the faith. (Christianity and Liberalism)