Both John and Charles Wesley returned to England deeply dissatisfied with their spiritual state.
Still heavily influenced by the Moravians they met with in London, the Wesleys joined in a 'Religious Society', and in May 1738 both underwent a profound spiritual experience. John famously described this in his Journal for 24 May 1738
"In the evening I went very unwillingly to a society in Aldersgate Street, where one was reading Luther's preface to the Epistle to the Romans. About a quarter before nine, while he was describing the change which God works in the heart through faith in Christ, I felt my heart strangely warmed. I felt I did trust in Christ, Christ alone for salvation, and an assurance was given me that he had taken away my sins, even mine and saved me from the law of sin and death."
Three days earlier, following his own 'conversion', Charles had written a hymn:
Where shall my wondering soul begin
How shall I all to heaven aspire?
A slave redeemed from death and sin,
A brand plucked from eternal fire,
How shall I equal triumphs raise,
Or sing my great Deliverer's praise?
Flowing from the complete assurance they felt in God's love and forgiveness, their faith was lived out in lives that went on to influence millions.
Charles went on to write over 6,000 hymns, while John used his organising genius to turn a spontaneous movement into structured body which became the origin of today's world-wide Methodist Church.