Apostasy as adultery
Concepts of apostasy perceived as adultery.
Key passages
Mk 8:38

For whoever is ashamed of me and my words in this adulterous and sinful generation, the Son of Man will also be ashamed of him when he comes in the glory of his Father with the holy angels.”

Jas 4:4

Adulterous people! Do you not know that friendship with the world is enmity with God? Therefore whoever wants to be a friend of the world makes himself an enemy of God.