It would seem to be a reasonable corollary to the Apostle John’s affirmation that he knew no greater joy than to know that his children walk in the truth (III John 4) that there is likely no greater sorrow than to see one’s own children walk away from the church and the gospel of Jesus Christ. This is no mere intellectual question but cuts us to our hearts.
The question above suggests that there are two different but related questions in play. First, how ought we to look at such a son, and second, how should such a son relate to the rest of the family? It is both a blessing and a curse that we are not able to see into the hearts of others. It is a curse when such might offer us assurance, a blessing when such might lead us to doubt.
Our first bedrock principle we should not lose sight of is that all humans, outside of our Lord, sin while we live on this planet. Your son is indeed in dark and grievous sin. So to, however, was King David when he took Uriah’s wife and his life. David, remember, was called the friend of God.
That said, the second bedrock principle is that those who practice gross and heinous sin have every reason to doubt their salvation. “No one knows the heart of another” can become too soft a pillow that misses the plain teaching of Scripture on what we can know. Paul wrote to the Galatians, “Now the works of the flesh are evident: sexual immorality, impurity, sensuality, idolatry, sorcery, enmity, strife, jealousy, fits of anger, rivalries, dissensions, divisions, envy, drunkenness, orgies and things like these. I warn you, as I warned you before, that those who do such things will not inherit the kingdom of God” (5:19-21).
Then there is this third bedrock principle- reaching the conclusion that a person is not a believer is not the same things as reaching the conclusion that he or she will never be a believer. Your son may be like David, given over to this sin for a season. He may be like Saint Augustine, who was brought to faith only after a riotous youth. Or, he may not be among those chosen before the foundation of time. We just can’t know for certain.
How then ought your family to treat him? The more important question is how ought the church to treat him. When your son professed Christ he surely came under the authority of a local expression of the body of Christ, the church. The elders there vowed to watch out for your son’s soul, and so now have a duty to bring to bear the grace of church discipline in his life. He should be called before the elders to repent, to turn from his sin. If he refuses, he should be barred from the Lord’s Table and from the table of those who belong to the Lord. He should be excommunicated, disfellowshipped. He should, that is, no longer be welcome at your own table as well. Your relationship with him changes from one wherein you believed one another to be bound together in the bonds of Christ to now being mere relatives. Yes you can be polite to him. You can be cordial to him. You should let him know that your hearts are broken, that you love him and always will, but that having left the faith; he has left that which defines your family. Remind him of the story of the prodigal son, and let him know that your prayers will always be that God the Holy Spirit would bring him to himself, that you might feast once again with him. Let there be no bitterness and rancor. Let him instead see your broken hearts.