Factoid: Thom Rainer’s research bears this out: One significant study done by and for mainline denominations found that in-depth teaching and preaching of orthodox Christian belief was the single best predictor of church participation. Strong Sunday Schools and scripturally- authoritative preaching engendered long-term health for the church.
Source: (Hunt, Josh. Double Your Class in Two Years or Less. Loveland, CO: Vital Ministry, 1997, p. 30. )