“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 they might be made manifest, that none of them were of us” (1Jo 2:19). Calvinists and the proponents of “Once Saved Always Saved” (OSAS) use this verse as proof that people leaving the local church never were saved to begin with otherwise they would have stayed and continued in the church. But it’s clear from the surrounding context just who “they” really are. “Little children, it is the last hour; and as you have heard that the Antichrist is coming, even now many antichrists have come, by which we know that it is the last hour” (1Jo 2:18). “They” are false teachers who deny the Son, “Who is a liar but he who denies that Jesus is the Christ? He is antichrist who denies the Father and the Son” (1Jo 2:22). John was not talking about churchgoers but men who were spreading false doctrine to deceive them, “These things I have written to you concerning those who try to deceive you” (1Jo 2:26).
Now since “they” are false teachers that came out from “us,” of which John includes himself, then “us” must have been the leaders of the early church with the 12 apostles at the core. In the first chapter of this epistle, John stated that fellowship with the apostles is necessary for having fellowship with God the Father and His Son Jesus Christ; “That which we have seen and heard we declare to you, that you also may have fellowship with us; and truly our fellowship is with the Father and with His Son Jesus Christ” (1Jo 1:3). Anyone teaching doctrine about Christ that is contrary to what the apostles taught is a false teacher and does not have fellowship with God, “Whoever denies the Son does not have the Father either; he who acknowledges the Son has the Father also” (1Jo 2:23).
According to OSAS proponents, verse 19 proves that those who leave the church never really were believers in the first place because if they had been then they would not have left. But John was not talking about professing Christians leaving the local church but about false teachers who were no longer in fellowship with the apostles. And it seems these heretics were using their past association with the apostles as credentials to gain acceptance by the churches. This was the main reason John was writing, to warn about these men.
So when he said “they were not of us,” did he mean that they never were in fellowship with the apostles? He could not have meant this because then “they would have continued with us” would not make sense. The only way they could have continued in fellowship is if they had a fellowship at one time. And if they had fellowship with them then they had fellowship with the Father and with the Son. So when “they went out from us” they must have been part of a larger group led by the apostles. Now it could be that these men were made to leave the fellowship; that they had been excommunicated through the discipline prescribed by Christ in Matthew 18:15-20. But regardless, John wanted his readers to recognize that they were not true teachers because they no longer had fellowship with “us” and therefore were not sent out by them.
“They went out from us, but they were not of us.” The last part of this statement “of us” is also translated “belonged to us” (1Jo 2:19 NIV). Yet a literal rendering of it is: “Out of us they came, but out of us they were not.” The same Greek preposition “ek” for “out” is used in both parts of the statement. Therefore, he was not saying that they never really belonged to that group or “of us” but that they were not sent out by that group.
Also, the last part of the verse is sometimes mistranslated: “none of them were of us” (1Jo 2:19 NKJV); “none of them belonged to us” (1Jo 2:19 NIV). But other translations get it right: “not all” (1Jo 2:19 KJV, YNG, WEB); “they all are not” (1Jo 2:19 ESV, NASB, RSV, ASV). It literally says “they are not all out of us.” It is not that none of them who left never really belonged to them but that not all of them who went out were sent out by them. This is crucial because if you hold to OSAS and that this verse supports it then you want it to say that none of them belonged. Because if it means that those who left the church never were believers in the first place then it also means that this is not true for all of them. In other words, some who left were believers thus disproving OSAS.
The entire verse literally says, “Out of us they came, but out of us they were not. For if they were out of us they had remained ever with us. But that they may be being made to appear that they are not all out of us.” John was saying that the way his readers would know these teachers were not sent out by the apostles is because they did not remain in fellowship with the apostles. Not all who came out from them were sent out by them because not all remained in fellowship with them. In closing, this verse is not about professing Christians leaving the church and therefore proving they were never saved. It is about false teachers who left fellowship with the apostles. The letter sent out from the Jerusalem church to Gentile believers explicitly says, “Since we have heard that some who went out from us have troubled you with words, unsettling your souls, saying, ‘You must be circumcised and keep the law’—to whom we gave no such commandment” (Act 15:24). Not all of them who went out from the apostles were sent out by them but only those who remained in fellowship with them. And fellowship with the apostles is fellowship with Jesus Christ and with the Father.