Ye simple souls that stray. C. Wesley (?) [Exhortation.] First published in Hymns for those that Seek and those that Have Redemption, 1747, in 7 stanzas of 8 lines. In 1780 it was given in the Wesleyan Hymn Book, No. 21, with considerable alterations, and the omission of st. iii. The authorship of this hymn has been a matter of dispute for many years, some claiming it for John Wesley on the authority of Mr. Henry Moore, and others for Charles on the word of Dr. Whitehead. The work in which it appeared is known to have been published by the two brothers, and the contents were unsigned. Under these circumstances the difficulty of determining the authorship is great. There is some probability in the suggestion that it was written by Charles, and that the extensive alterations made therein for the Wesleyan Hymn Book, in 1780, were the work of his brother. Original text, Poetical Works, 1868-72, vol. iv. p. 230.
--John Julian, Dictionary of Hymnology (1907)
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The research of Randy Maddox (Duke Divinity School, Center for Wesleyan Studies, https://divinity.duke.edu/initiatives/cswt/charles-published-verse) indicates that the 1747 publication was all by Charles Wesley, and that John Wesley made considerable revisions in the 1788 edition.
Barry Johnson