They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us.
1 John 2:19
King James Version (public domain)
Traditionally attributed to John · 1st century AD · One of the twelve apostles of Jesus; the "beloved disciple"
Context
17And the world passeth away, and the lust thereof: but he that doeth the will of God abideth for ever.
18Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time.
19They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us.
20But ye have an unction from the Holy One, and ye know all things.
21I have not written unto you because ye know not the truth, but because ye know it, and that no lie is of the truth.