What does the Bible teach about apostasy?

In the sermon, the preacher discusses apostasy and emphasizes that those who have truly experienced Christ cannot ultimately deny Him. As noted in 1 John 2:19, 'They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us.' This indicates that true believers, despite their struggles with doubt, retain their connection with Christ, as seen in Peter's own denial that did not sever his relationship with the Savior. Apostasy, then, refers to those who appear to believe but ultimately turn away, revealing their true nature never to have been part of the body of Christ.