Contaminated Salt

What does it mean that where Christ has paid for a sinner they cannot turn back unto perdition? Why did the LORD purpose that Peter fall by betraying Christ? Why can we never put any confidence in our flesh? How can anyone have any type of hearing? What is Spiritual hearing? What is presumption when it comes to Christ? Is all that God makes good? Where did evil come in and why? Will the carnal nature ever improve? What does the Word mean when Paul says in me dwells no good? What is depravity and are any of us as bad as we could be? Is everything we do tainted with sin? Do we war within ourselves? What is the flesh captive too? What does it mean to serve the Law of God? How is the salt a picture of Christ? What is perverted grace? How is anything a man does to salt a contamination and a picture of works religion perverting the Gospel of Christ?