Chapter 15 is entitled “John Wesley becomes an Open-Air Preacher” highlights the transition of Whitefield’s burgeoning ministry in Bristol to John Wesley.
Whitefield was holding ‘nearly thirty meetings a week with audiences which totaled – according to his estimates – forty or fifty thousand’. [pg 273]
Wesley was Whitefield’s fourth choice after Hutchins, Kinchin and Harris. After Wesley arrived in Bristol to take over Whitefield’s work and seeing Whitefield preach his initial two days, Saturday evening and Sunday, Wesley wrote in his journal, “I could scarce reconcile myself to this strange way of preaching in the fields, of which he set me an example on Sunday; having been all my life (till very lately) so tenacious of every point relating to decency and order, that I should have thought the saving of souls almost a sin if it had not been done in a church.” [pg 274].
You see in Chapter 15 the development of Wesley’s comfort with open air preaching and his increased skill which he deploys to maximize the opportunity.
Dallimore writes of Wesley’s thought that led him to accept Whitefield’s offer to take over his work:
“Wesley was deeply moved by the prospect which such a ministry opened up. The reaching of vast numbers of mankind, the freedom to range at will and preach wherever opportunity afforded – these advantages could not fail to make a powerful appeal to so earnest man.” [pg 275]
Thus you have the beginning of John Wesley’s expansive and powerful open air ministry.