A portion of a letter by John Wesley to John Bennet, a lay-preacher of the Methodist Societies. The letter was written in June 1744.
If the Bible be true, then none is a Christian who has not the marks of a Christian there laid down. One of these is the love of God, which must be felt (if it is in the soul) as much as fire upon the body. Another is the witness of God's Spirit with my spirit that I am a child of God. Till I have these marks I am not a Christian; and no power can give me these but that which made the world.
The Letters of John Wesley, edited by John Telford, Epworth Press, 1931, also online at www.wesley.nnu.edu/John_Wesley/letters/index.htm