If a Christian "converts" to Judaism or Islam (or any of the Abrahamic religions), is he still considered saved as a Christian? What if he/she converted from Trinitarian to Uniterian? This is a general Christian question, so I am requesting an overview of Christian positions on such conversions.

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    I was thinking of staying in the Abrahamic religions, but I don't see why it couldn't apply. One could expand on it and ponder denominations, but that's too broad of a scope for this question. – user1054 Jul 5 '12 at 20:32
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    @DJClayworth: I'm also not sure one can "convert" to it unless you are already ethnically Jewish. – Jon Ericson Jul 5 '12 at 22:24
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    Apostasy is Apostasy no matter what the ultimate endind theology is. – Affable Geek Jul 6 '12 at 0:30
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    @JonEricson converting to Judaism is possible en.wikipedia.org/wiki/Conversion_to_Judaism – Andrew Jul 6 '12 at 14:46
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    @KorvinStarmast Certainly reasonable in this case, especially since the top answer provides exactly that – an overview. But even that answer only deals with the "leaving the faith" aspect, and doesn't address the difference between converting to Islam vs. Unitarianism. Overview questions for all of Christendom make me nervous, though I'll admit they can work sometimes. But this seems to be even broader than most, as it asks about two different types of apostasy for all of Christendom. – Nathaniel is protesting Jan 23 '17 at 19:21

There is no consensus among Christians on this question. Assuming that the conversion is genuine and permanent, rather than momentary weakness, the three main schools of thought that apply to this issue are:

Conditional Security

According to this view, Christians can lose their salvation. Thus, a Christian who converted to another religion would be seen to have lost his salvation, if he had it in the first place. Christians who hold this view, such as Arminians, would answer "No".

Perseverance of the Saints

Another school of thought is that Christians cannot lose their salvation, and that true believers will persevere till the end. According to this view, although true believers may fall and stumble temporarily, they will never fall away permanently. A supposed Christian who permanently converted would be seen as having never been a genuine Christian in the first place. Like the first view, Christians who hold this view would answer "No".

Free Grace Theology

Free Grace Theology is a view in which Christians cannot lose their salvation, and may fall away permanently. This view teaches that the saved may or may not become disciples, and may or may not undergo the process of sanctification. Christians may believe in Christ at one point, and subsequently forsake any identity with Christianity. Christians who hold this view would answer "Yes".

  • Good summary of the primary (at least that I'm aware of) thoughts on this issue. – wax eagle Jul 6 '12 at 12:34
  • What if he/she converted from Trinitarian to Uniterian? – user1054 Jul 6 '12 at 12:43
  • @DanAndrews could you add that specifier to the question? – wax eagle Jul 6 '12 at 14:25

The Apostle John addresses this issue in his first epistle:

They went out from us, but they were not of us; for if they had been of us, they would have continued with us. But they went out, that it might become plain that they all are not of us. 1 John 2:19 ESV

This teaches that those who leave [Christianity] were never really Christians.

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    My recollection is that this is not a general description of all Christians who leave, but an attack on some specific group of "false teachers". It's also rather stroppy. – TRiG Jul 6 '12 at 13:10
  • What you describe may be true for one denomination, but the Catholic Church believes that once someone has been baptized catholic, if they leave the church they become lapsed catholics who will/may return one day. (For the latter purpose a "Catholics Come Home" lay movement has been organized and is active in the US). So while outside of the communion, there is always a path back through penance and reconciliation. – KorvinStarmast Jan 23 '17 at 18:34