The "structural elements of man" (who is "one in body and soul") that are "permanent" on 1) the level of nature and 2) the even more fundamental (!) level of grace

"To call into question the permanent structural elements of man which are connected with his own bodily dimension would not only conflict with common experience, but would render meaningless Jesus' reference to the "beginning" [("principii")], precisely where the social and cultural context of the time had distorted the primordial meaning and the role of certain moral norms (cf. Mt 19:1-9). This is the reason why 'the Church affirms that underlying so many changes there are some things which do not change and are ultimately founded upon Christ, who is the same yesterday and today and for ever' [(Gaudium et spes 10)]. Christ is the "Beginning" [("Principium")] who, having taken on human nature, definitively illumines it in its constitutive elements and in its dynamism of charity towards God and neighbour."

     Veritatis splendor 53.  "in its constitutive elements and in its dynamism of charity", i.e. 1) in nature (cardinal), and 2) in grace (theologal).