Wesleyan theology, otherwise known as Wesleyan–Arminian theology, or Methodist theology, is a theological tradition in Protestant Christianity based upon the ministry of the 18th-century evangelical reformer brothers John Wesley and Charles Wesley. More broadly it refers to the theological system inferred from the various sermons (e.g. the Forty-four Sermons), theological treatises, letters, journals, diaries, hymns, and other spiritual writings of the Wesleys and their contemporary coadjutors such as John William Fletcher, Methodism's systematic theologian.
In 1736, the Wesley brothers travelled to the Georgia colony in America as Christian missionaries; they left rather disheartened at what they saw. Both of them subsequently had "religious experiences", especially John in 1738, being greatly influenced by the Moravian Christians. They began to organize a renewal movement within the Church of England to focus on personal faith and holiness, putting emphasis on the importance of growth in grace after the New Birth. Unique to Wesleyan Methodism is its definition of sin: a "voluntary transgression of a known law of God." Methodist doctrine teaches that the life of a Christian subsequent to the New Birth should be characterized by holiness, living victoriously over sin. Calling it "the grand depositum" of the Methodist faith, John Wesley taught that the propagation of the doctrine of entire sanctification—the work of grace that enables Christians to be made perfect in love and be made free from the carnal nature—was the reason that God raised up the Methodists in the world.