Our Lord said, "Unless a man be born of water and the Holy Ghost he cannot enter the Kingdom of Heaven." This water means literally water, poured on you, sprinkled on you, or into which you are immersed. Our Lord can speak metaphorically, as must everyone who speaks at all, at times. But with regard to this water, He is not so speaking. Nothing in His utterance indicates this; nothing in the practice of the Church vouchsafes it; and nothing in the teachings of the Doctors or the definitions of the Popes, the behavior of the Apostles, or the manner of dying of the martyrs, will allow the water Christ refers to, to be other than the water of the kind He was immersed in the River Jordan, when His Father’s voice was saying, "This is My Beloved Son, in Whom I am well pleased." (Matt. 3:17.)
When you hear a theologian saying, "I know that was what Christ said, but first we must understand what He means," you know you have a skeptic on your hands, who is blasphemously trying to improve on the utterances of Jesus. He is implicitly telling you that Jesus gave us vague notions as to what Baptism meant, and that he (the theologian) is now going to clarify this matter. - Fr. Feeney