John Wesley differentiated between essential beliefs and nonessential beliefs which he called "opinions." He believed that Christians should be unified in love but need not have identical beliefs or practice identical rituals. In his sermon on "Catholic Spirit" he said:
But although a difference in opinions or modes of worship may prevent an entire external union, yet need it prevent our union in affection? Though we cannot think alike, may we not love alike? May we not be of one heart, though we are not of one opinion? Without all doubt, we may. Herein all the children of God may unite, notwithstanding these smaller differences. These remaining as they are, they may forward one another in love and in good works.
Wesley, though he had his own personal lapses in this area, opposed religious bigotry and did not allow it in the societies, as the following story reveals.
by J. B. Wakeley, 19th Century Methodist Historian
Whenever bigotry dwelt it found no place in the bosom of John Wesley. A more catholic spirit never dwelt in the bosom of man. There was a man by the name of Acourt in the London Societies, who was not only a bigot, but a troubler of Israel, and who would argue in favor of his peculiar tenets at the devotional meetings. Charles Wesley heard of his conduct, and denied him admission. The next meeting, when John was present, Acourt came and inquired of him if he had been excluded for his opinions. Mr. Wesley asked, "Which opinions?" He replied, "That of election. I hold that a certain number are elected from eternity, and they must and shall be saved, and the rest of mankind must and shall be damned." He stated, "There are others in the Society of the same faith." Mr. Wesley replied that he never questioned their opinions. All he demanded was, that they should not trouble others by disputing about them. He said, "Nay, but I will dispute about them. You are all wrong, and I am determined to set you right." Mr. Wesley answered, "I fear your coming with this view will neither profit you nor us." Acourt said, "I will go, then, and tell all the world that you and your brother are false prophets, and I tell you that in a fortnight you will all be in confusion." He left, but his prediction proved false.
Source: J. B. Wakeley, Anecdotes of the Wesleys: Illustrative of Their Character and Personal History (New York: Nelson & Phillips, 1869).