What is Reformed Theology/Calvinism 12: Defending Perseverance of the Saints

Can a genuine Christian lost his salvation? What about Hebrews 6:1-8 or Galatians 5:4? Are those texts speaking of real Christians who turn away from the faith or is it just about apostates? What does it mean to make shipwreck of one's faith? What does it mean to make shipwreck of one's faith? How does 1 John 2:19 answer these questions definitively? How does "once saved, always saved" give the wrong idea about endurance in the faith? What is mean by the phrase "eternal security"?