What is apostasy and how does it relate to electing grace?

Apostasy is a significant biblical concept referenced by Paul in 2 Thessalonians 2:3, where it describes individuals who profess faith but ultimately reject the truth. This is particularly related to electing grace because true believers, those chosen by God, will not fall away. While some may appear to embrace the gospel, their eventual departure indicates that they were never genuinely elected unto salvation. Understanding that electing grace guarantees the perseverance of the saints helps Christians discern the nature of true faith versus mere profession of faith, emphasizing the importance of genuine belief that is sustained by God's grace.