A seemingly extreme manner of disassociating with “unruly” brethren is laid out in verses 14 and 15. There is the instruction for the rest of the body to separate from those who do not take to heart the instructions of godliness that are posited. This separation does not mean to never speak with such a person ever again, rather it is in terms of not mingling with them in a more comfortable, social setting, as if one were to pretend that everything is normal and okay.
Some may see this exclusion as harsh and unloving, but verse 15 exposes this way of dealing with unruly men as actually loving. It is a desire to see them not only walk in a manner consistent to the sanctified life to which they have been called merely in an external way, but it is because this outward walk is a fruit of what is in the heart. Since from out of the heart flow the issues of life, then this manner of dealing with someone is a corporate expression of admonition and hope for inward repentance and change. It is a love for them to be vigilant and sober so that the deluding influence of lawlessness and false belief does not continue to consume their hearts and lead to their ultimate destruction.
Though unrepentant sin is to be resolutely dealt with within the church, the purpose of this exclusion is not to ultimately reject someone, but to protect the rest of the church from being negatively influenced, and to restore the wandering sheep back to the fold.
A true friend is one that can speak truthfully to another, and to behave toward them truthfully, with the intention of seeing them benefited. A hateful parent does nothing to discipline their children, but a loving parent corrects and instructs their children when they do wrong. They do this because they know that it is for their good. So, admonitions and necessary steps must be taken in brotherly love out of a desire for their eternal well being.
Calvin said in regards to 2 Corinthians 2:7 and on this passage: “Hence we see that the use of discipline ought to be in such a way as to consult the welfare of those on whom the Church inflicts punishment. Now, it cannot but be that severity will fret, when it goes beyond due bounds. Hence, if we wish to do good, gentleness and mildness are necessary, that those that are reproved may know that they are nevertheless loved.”