Ezechiel 3:20 Moreover if the just man shall turn away from his justice, and shall commit iniquity: I will lay a stumblingblock before him, he shall die, because thou hast not given him warning: he shall die in his sin, and his justices which he hath done, shall not be remembered: but I will require his blood at thy hand. (If the Just man can turn away, what about those telling me "I am saved?")
John 3:16 - What is the definition of eternal? It means without end.
Additionally, since salvation is totally an act of God, to say that it is my perseverance which determines my salvation, takes it out of His hands and puts it in mine. That is unscriptural.
Ezekiel Ch.18 Vv.20-27
The soul that sinneth, it shall die. The son shall not bear the iniquity of the father, neither shall the father bear the iniquity of the son: the righteousness of the righteous shall be upon him, and the wickedness of the wicked shall be upon him.
But if the wicked will turn from all his sins that he hath committed, and keep all my statutes, and do that which is lawful and right, he shall surely live, he shall not die.
All his transgressions that he hath committed, they shall not be mentioned unto him: in his righteousness that he hath done he shall live.
Have I any pleasure at all that the wicked should die? saith the Lord GOD: and not that he should return from his ways, and live?
But when the righteous turneth away from his righteousness, and committeth iniquity, and doeth according to all the abominations that the wicked man doeth, shall he live? All his righteousness that he hath done shall not be mentioned: in his trespass that he hath trespassed, and in his sin that he hath sinned, in them shall he die.
Yet ye say, The way of the Lord is not equal. Hear now, O house of Israel; Is not my way equal? are not your ways unequal?
When a righteous man turneth away from his righteousness, and committeth iniquity, and dieth in them; for his iniquity that he hath done shall he die.
Again, when the wicked man turneth away from his wickedness that he hath committed, and doeth that which is lawful and right, he shall save his soul alive.