For to this end also did I write, that I might know the proof of you, whether you be obedient in all things.
Read Chapter 2
As far as anyone can tell, Paul was commending the Corinthians for their obedience in other respects. They had already put matters right in their church administration, and now he was asking them to be obedient in this matter as well. Commentary on Paul’s Epistles.
This was another reason why I wrote my former letter to you, viz. to try your obedience, and your attachment to the faith, and that I might know whether the difference of opinion which prevailed among you had prevented you from being obedient. (Calmet)
Others explain it thus: I have written this second letter to you to try your obedience, and to know if you will pay the same obedience to my orders, when I tell you to receive the incestuous man into your communion, as you did when I told you to separate him from your communion. (Estius and Theodoret)
Paul needs to see that the Corinthians are as obedient in restoring the sinner as they had been in punishing him. For the punishment might have proceeded in part from envy and malice, but if they now proceed to restore him in love, that will show that their obedience is pure. This is the test of true disciples: if they obey not only when ordered to do something but on their own as well.
5. For to this end also did I write to you , that I might know the proof of you, whether you are obedient in all things; not only in cutting off but also in reuniting. Do you see how here again he brings the danger to their doors. For as when he sinned, he alarmed their minds, except they should cut him off, saying, A little leaven leavens the whole lump, 1 Corinthians 5:6 and several other things; so here too again he confronts them with the fear of disobedience, as good as saying, 'As then ye had to consult not for him, but for yourselves too, so now must ye not less for yourselves than for him; lest ye seem to be of such as love contention and have not human sensibilities, and not to be in all things obedient. And hence he says, For to this end also did I write to you, that I might know the proof of you, whether you are obedient in all things.
For the former instance might have seemed to proceed even of envy and malice, but this shows very especially the obedience to be pure, and...