Populorum Progressio §16

¹⁶ Self-development, however, is not left up to man's option. Just as the whole of creation is ordered toward its Creator, so too the rational creature should of his own accord direct his life to God, the first truth and the highest good. Thus human self-fulfillment may be said to sum up our obligations. Moreover, this harmonious integration of our human nature, carried through by personal effort and responsible activity, is destined for a higher state of perfection. United with the life-giving Christ, man's life is newly enhanced; it acquires a transcendent humanism which surpasses its nature and bestows new fullness of life. This is the highest goal of human self-fulfillment.