An evil and unbelieving heart develops through neglect, compromise, and resistance to Scripture, but a vigilant believer guards the heart through obedience and truth.
Drifting Away: Avoid an Evil, Unbelieving Heart, in Falling Away From the Living God
Hebrews warns against drifting into unbelief. Christians must guard their hearts and remain steadfast in faith to avoid falling away from the living God.

