Paul heard that one of the Corinthian Christians had committed a serious sexual sin and was not repentant (1 Cor 5:1). Paul knew that he had to make it clear that this man was excommunicated (1 Cor 5:3ff; 5:13). However, some in the Corinthian church were condoning this sin (see 1 Cor 5:2), and Paul could not be present personally to speak with the person excommunicated or the other members of the church (1 Cor 5:3). Furthermore, it was questionable whether Paul's authority in the Corinthian church would be accepted (see 2 Cor 11:5ff).
Paul had several reasons not to address the sin in the Corinthian church immediately. However, he knew that it was God's will for him to act without delay, for "a little yeast has its effect all through the dough" (1 Cor 5:6). Sin is like cancer. It can spread quickly. Hence, immediate action is necessary no matter what the obstacles.
Today, a permissive attitude toward sin is pervasive even in much of the Church. Although this may appear to be compassionate, loving, and "non-judgmental," at best, permissiveness toward sin is a paralyzing confusion. Permissiveness is a refusal to be responsible, loving, and just. It is out of touch with reality and makes matters worse immediately and possibly forever.
So let us follow Paul's example in acting immediately regarding sin and having "zero tolerance" for our own sins and those of others. In this way, we will hate the sin and truly love the sinner.