Pope John Paul II
Veritatis Splendor §49
Veritatis Splendor: Regarding Certain Fundamental Questions of the Church's Moral Teaching
49 A doctrine which dissociates the moral act from the bodily dimensions of its exercise is contrary to the teaching of Scripture and Tradition. Such a doctrine revives, in new forms, certain ancient errors which have always been opposed by the Church, inasmuch as they reduce the human person to a "spiritual" and purely formal freedom. This reduction misunderstands the moral meaning of the body and of kinds of behaviour involving it (cf. 1 Cor 6:19). Saint Paul declares that "the immoral, idolaters, adulterers, sexual perverts, thieves, the greedy, drunkards, revilers, robbers" are excluded from the Kingdom of God (cf. 1 Cor 6:9). This condemnation — repeated by the Council of Trent" — lists as "mortal sins" or "immoral practices" certain specific kinds of behaviour the wilful acceptance of which prevents believers from sharing in the inheritance promised to them. In fact, body and soul are inseparable: in the person, in the willing agent and in the deliberate act, they stand or fall together.
Source: Veritatis Splendor (Vatican.va)