In his dispute with the Pharisees (Mt 19: 3 ff), Christ takes marriage back to God’s plan in the beginning, seen in Genesis, which sets forth a proper understanding of the nature of man and woman, made in God’s image, as well as the unity and indissolubility of marriage.
In the beginning, Adam and Eve experienced their communion as a real participation in God’s own mystery of love. The very sentiment of sexual desire as God created it to be was to love as God loves in the sincere gift of self. Since this call to love is the summary of the Gospel, John Paul II can say that if we live according to the nuptial meaning of our bodies, we “fulfil the very meaning of [our] being and existence” (Jan 16, 1980). It is for this reason that a man clings to his wife and they become “one flesh” (Gen 2:24). The experiences of Original Man can be divided into three phases: original solitude, original unity and original nakedness. Although they appear in a sequential order, the appearance of the one does not diminish the experience before it. This means that the experience of unity does not eliminate the experience of solitude, and likewise, nakedness does not erase the experience of solitude and unity (c.f. TOB 10:4 for a reference of a “twofold solitude”, that presupposes the idea that unity does not diminish the fruits of solitude). Instead, each experience builds upon the one before it, forming a solid reconstruction of man’s experiences before sin. This is referred to as original innocence.
For a concise view, download the PDF: Original Man
(Adam and Eve in the Garden of Eden, detail (Karlsbad 1745 – Rome 1829), Peter Wenzel, Vatican Museum)