Scriptural Proof that the Saved can be Lost

QUESTION: What do you regard as the strongest Scriptural proof that a person who has been truly converted may be finally and eternally lost?

ANSWER: The words of Christ in John 15:1, 6 can have no other meaning. A person who is "a branch in me" (Christ) may become fruitless and "withered" and "cast forth as a branch," and "gathered" and "cast into the fire," and "burned." If this figurative language is not a solemn, deliberate and graphic declaration of the possible perdition of a soul once regenerated and savingly united with Christ, then it is impossible to express this idea in human language. These words should lead every professor of Christ to ask himself daily, am I bringing forth such fruit as Jesus Christ is looking for, (1) the fruit of the Spirit (Gal. 5:22) and (2) the fruit of saved souls (John 4:36) "How a man can be 'in Christ,'" says Bishop Westcott, "and yet afterwards separate himself from him, is a mystery neither greater nor less than that involved in the fall of a creature created innocent." The scholarly bishop must have forgotten that the fall of a Christian under the assaults of the devil is less mysterious than the fall of the angels who fell without temptation.

— Steele's Answers pp. 197, 198.