Is revival a spiritual science? Charles Finney (1792-1875), lawyer turned Presbyterian minister, led an estimated half million people to the Lord during the Second Great Awakening (1790-1840). Finney believed that God gives us means to get a spiritual harvest in the same way that God gives the farmer means to get a physical harvest.
Lectures on Revivals of Religion brings together twenty-three lectures Charles Finney gave to his church during the middle of the 19th century. You can download or read them online for free at https://www.ccel.org/ccel/finney/revivals.html