Charles Grandison Finney is known as the 'Father of Modern Revivalism'. He was a leader in the 'Second Great Awakening' in the United States, serving as a Presbyterian, then Congregationalist, minister and religious writer.
Finney's significance was in innovative preaching and service procedure. For instance, he allowed women to pray out loud and saved 'anxious' seats in the congregation for people interested in conversion.
He also supported abolitionism, using his preaching platform to denounce slavery. Other social reforms that he supported (and spoke for) were equal educational opportunities for women, and African Americans.
The Second Great Awakening was a period, from 1790 to 1850, that led to the enrolment of millions of new members, and the creation of several new denominations. Amending various social 'evils' through this Awakening was also thought to be aiding the preparation of humanity for the anticipated second coming of Jesus Christ.
Charles Grandison Finney is significant in US history because he was one of the major forces behind the social changes known as the Second Great Awakening. This was a major religious revival that happened in the early 1800s.
The Second Great Awakening was important because it was a reaction to the less religious ideas of the Enlightenment and a reaction to the changes that were occurring in the US society and economy in the early 1800s. The Second Great Awakening was important for people's religious lives, but it was also important because it gave rise to a number of reform movements (such as abolitionism) that were meant to improve society.
Finney, then, is important because he helped to bring about the Second Great Awakening.