Q&A: Core doctrines vs. peripheral doctrines — spiderweb illustration; Mormonism example

Mike uses a spiderweb analogy: core doctrines (identity of Christ, salvation by grace through faith apart from works) are at the center — getting these wrong destroys the whole web. Peripheral doctrines (speaking in tongues, church government, excommunication practices) are at the outside — getting them wrong damages the web but doesn't destroy it. Mormonism is an example of tampering with the core gospel message (salvation by grace plus works).