18 Children, it is the last hour; and just as you heard that antichrist is coming, even now many antichrists have appeared; from this we know that it is the last hour. 19 They went out from us, but they were not really of us; for if they had been of us, they would have remained with us; but they went out, so that it would be shown that they all are not of us. 20 But you have an anointing from the Holy One, and you all know. 21 I have not written to you because you do not know the truth, but because you do know it, and because no lie is of the truth. 22 Who is the liar but the one who denies that Jesus is the Christ? This is the antichrist, the one who denies the Father and the Son. 23 Whoever denies the Son does not have the Father; the one who confesses the Son has the Father also. 1 John 2:18-23
To whom is John referring in verse 19? Who are “they” who went out from us? According to the context, these are ‘antichrists’. They ‘lie’. They deny ‘that Jesus is the Christ’ and they deny ‘the Father and the Son’. It should not surprise us that at some point they profess a faith they do not have and never had.
There is another group entirely who no longer believe the faith they once professed. These are people whose faith was genuine but fell into sin and who hardened their hearts. These are people who have turned away from Christ because they want to enjoy the things of this world.
To avoid becoming part of this latter group, we must heed the many warnings in Scripture against falling away.
– SSxG