There is nothing wrong with sharing your concern for those who are heading in the wrong direction or listening to voices only capable of causing harm.
This has always been the motivation of the apostle Paul. His concern is great, and it is a mark of love for the churches he founded as well as for the churches founded by those who were sent from the churches he founded.
Paul never stops caring. He is never willing to write off any church – but instead writes to the churches warning them of the potential dangers for themselves inherent in stating the simplicity of the gospel of the Lord Jesus Christ.
Words of instruction and correction are not always well-received, so there is an associated risk for Paul that his words will be rejected, and himself as well.
I think of all the great examples Paul provided his concern and continued caring may have been his greatest. After all, not all of us can be great theologians or authors or giants of the faith as Paul certainly was, but all of us can care enough about those we love to warn them when they are headed in the wrong direction or listening to wrong voices.
And Paul is not ashamed to admit HOW MUCH he cares. Whether they care for him or not is never the issue with the apostle Paul. His concern for them is as great as his concern for the continuation of the gospel of the Lord Jesus Christ.
This is a shepherd’s heart personified. The most loving thing any shepherd can do for his sheep is to teach them truth – whether it is well-received or not. Shared compassionate truth = love.
From a distance, Paul understands the threats to the churches at Colosse and Laodocia are existential. They will tear these churches apart and turn people away from Christ if given voice. The ideas presented by the gnostics were compelling because they appealed to the flesh as well as the mind. Even though Paul had not planted these churches – and even though he had never visited them – and may not have known many or even any of the people populating those churches, Paul still cared enough to pray for them and instruct them in the fallacies of gnosticism and in the truth of the simplicity of the gospel of the Lord Jesus Christ.
Additionally, Paul understand the grave danger inherent in the simple fact the gnostics were present in these churches, and he was not – and possibly could never be. But still he wrote to them, even from prison, because he really cared for them in Christ. His motive was never to draw attention to himself, but to demonstrate his love in Christ for them. If they continued to listen to the gnostics and their lies, they could never say they had not heard the truth.