1 Corinthians 4:18
“Now some are puffed up, as though I were not coming unto you.” For there he glances both at them and at certain others, casting down their highmindedness: since the love of preeminence is in fault, when men abuse the absence of their teacher for their own self-will. For when he addresses himself unto the people, observe how he does it by way of appeal to their sense of shame; when unto the originators of the mischief, his manner is more vehement. Thus unto the former he says, “We are the offscouring of all:” and soothing them he says, “Not to shame you I write these things;” but to the latter, “Now as though I were not coming to you, some are puffed up;” showing that their self-will argued a childish turn of mind. For so boys in the absence of their master wax more negligent.
This then is one thing here indicated; and another is that his presence was sufficient for their correction. For as the presence of a lion makes all living creatures shrink away, so also does that of Paul the corrupters of the Church.
Source: Homilies on First Corinthians (New Advent)