Pope St. John Paul II
“In fact, in order to remain in the relation of the ‘sincere gift of self’ and in order to become a gift, each for the other, through their whole humanity made of femininity and masculinity (also in reference to the perspective that Genesis 2:24 speaks about), they must be free in exactly this way. Here we mean freedom above all in self-mastery (self-domination). Under this aspect, self-mastery is indispensable in order for man to be able to ‘give himself,’ in order for him to become a gift, in order for him (referring to the words of the Council) to be able to ‘find himself fully’ through ‘a sincere gift of self’ [Gaudium et Spes, 24:3].”
Source: Pope John Paul II, Man and Woman He Created Them, Pauline Books and Media, 2006.