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.1 John 2:19(NASB)
False teachers who profess to be Christians and unbiblical doctrine that is not founded on Scripture is not only evident today, but was starting to seep into church life during the times of the apostle. Together with the lust of the flesh, the lust of the eye, and the pride of life, false teaching was one of the main problems in the early church and was vigorously addressed by all the apostles.
False doctrine and deceptive teachings proliferate today, and in this passage John gives us some strategies in identifying those professing the truth, yet believing an erroneous gospel. Such people have, "a form of godliness, yet deny the truth of the gospel of grace," delivered to us by Christ's apostles and recorded in Scripture.
Indeed, John labels these men as 'antichrists' - not THE Antichrist who will take his place on the world stage during the Great Tribulation, but those that oppose Christ, resist the Spirit, and contradict the gospel of God. He explains in this verse that these false apostles and teachers, "went out from us - but were not really part of us."
These charlatans had come into the church giving the impression they were true believers. However, they eventually withdrew from the Body of Christ because their heart was not true to the truth and because they expounded lies and deceit. These deceivers were not united in spirit and truth with the apostles or the rest of the Body of Christ, but propounded a different gospel.
These people have serious doctrinal differences from Christ's true apostles and when attempting to fellowship with true believers who walk in spirit and truth, they become uncomfortable in their company and expose themselves for who they are. As John explained, "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."
Although they may deceive some genuine Christians, these people have no unity with the Body and their exit from our company identifies their hidden agenda. Like all the apostles of Christ, John is calling all believers to walk in spirit and truth and to live a life that is consecrated to God. He is encouraging perseverance in the faith, an unswerving trust in God's Word, and a demonstration of good works. Jesus Himself said we would know those that are 'not really of us' - by their works.
Walking in the unity of the faith, being led by the Spirit, standing firm on the Word of God, holding fast to the glorious gospel of Christ, persevering under trials, and carrying out the good works that God has prepared for us to do, should be the normal way Christians live. However, godly living is not inevitable and sadly there are some true believers, (as can be seen in Paul's letter to the Corinthians) who display carnality and may not be in fellowship with other believers or God, for an extended period.
Someone who has been saved by grace through faith in Christ whose life is not a testimony of the truth... though eternally saved and secure in Christ because of their faith in Him, will live a defeated life and dishonour the Lord Who bought them. Their life will be saved, but they will not receive a reward for living godly in Christ Jesus. They will be saved... 'as if by fire'.
We are ALL called to grow in grace and become spiritually mature... but not all believers develop at the same rate and sadly, some spend part of their life in fleshly pursuits. We are NOT to be the judge of a person's salvation - only God can read the state of a man's heart. Only the Spirit of God can breathe life into him - which is by faith in Christ. However we ARE to judge their good works.
This verse is addressing issues of serious doctrinal differences, including believing a false gospel and following another Jesus. Those identified here are unsaved and although they give the outward appearance of godliness, they deny the truth of the glorious gospel of God, "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. They went out, so that it would be manifested that they all are not of us."
Heavenly Father, thank You for the many teachings that warn about false teachers. Help me to be discerning when meeting those who pretend to be believers, yet live a lie and believe a false gospel. Give me wisdom I pray and help me to live in unity of the Body, to walk in spirit and truth, to remain doctrinally sound, and to live a life that honours Your name. Protect those that are deceived by false teachers and give them discernment to know the truth. This I ask in Jesus' name, AMEN.