17 Boast not of your baptism because I call it a real baptism. Behold, I say that it is so; the whole Catholic Church says that it is so; the dove regards it, and acknowledges it, and groans because you have it without; she sees therein what she may acknowledge, sees also what she may correct. It is a real baptism, come. Thou boastest that it is real, and yet will you not come? What then of the wicked, who do not belong to the dove? Says the dove to you, Even the wicked, among whom I groan, who belong not to my members, and it must needs be that I groan among them, have not they that which you boast of having? Have not many drunkards baptism? Have not many covetous? Have not many idolaters, and, what is worse, who are such by stealth? Do not the pagans resort, or at least did resort, publicly to idols? And now Christians secretly seek out diviners and consult astrologers. And yet these have baptism; but the dove groans among ravens. Why then do you boast in the having it? This that you have, the wicked man also has. Have humility, charity, peace; have the good thing which as yet you have not, so that the good thing which you have may profit you.
Source: Tractates on the Gospel of John (New Advent)