Can Christians Lose Their Salvation?

Whether they call it "eternal security," "perseverance of the saints," or "once saved, always saved," many Protestants believe that once a person enters into a saving relationship with Jesus Christ, that they can never lose their salvation. And there are Bible verses that DO seem to say that... if you read them a certain way. But if this is what the Bible really teaches, why didn't the early Christians seem to know about this teaching? And why do so many Christians today read the Bible as denying eternal security? Chapters 0:00 - Intro 0:09 - Overview 2:05 - Red flags 8:16 - Piper's answer 15:27 -The Greek "to call" 18:17 - No Security readings 19:18 - God's faithfulness, not ours 20:49 - External threats to salvation 24:30 - Implicit Conditionality 28:07 - A case against security 37:20 - Scripture and deadly Sin 41:12 - Biblical examples of mortal sin 47:05 - Hebrews and sin 58:21 - Eternal security and apostasy