Throughout his life, John Wesley held to an orthodox view of the Holy Spirit as the third person of the Godhead. It was his trinitarian understanding of the God that informed his view of the Spirit's role in the Christian life. So adamant was Wesley’s conviction of this doctrine that he noted at the conclusion of his homily on the Trinity:
But I know not how anyone can be a Christian believer till “he hath” (as John speaks) “the witness in himself”; till “the Spirit of God witnesses with his spirit that he is a child of God”—that is, in effect, till God the Holy Ghost witnesses that God the Father has accepted him through the merits of God the Son—and having this witness he honours the Son and the blessed Spirit “even as he honours the Father. . . . Therefore I do not see how it is possible for any to have vital religion who denies that these three are one.[1]
In Wesley's view, one can not have an authentic "inner witness" of the Spirit without an equally orthodox view of the Trinity. Non-trinitarians beware. Wesley's words remind us that no experience of the Spirit whether it be in vision, spiritual gift or personal encounter is deemed authentic if one denounces a trinitarian understanding of God. The gracious would say such manifestations are heterodox. The honest call it hersey. Wesley would surely support the proposition that without an orthodox view of the Trinity one cannot claim an authentic experience of the Spirit.
Footnote
1. John Wesley, “On the Trinity,” The Bicentennial Edition of The Works of John Wesley, ed. Reginald Ward and Richard P. Heitzenrater (Nashville, TN: Abingdon Press, 1990), 2:385–86.