39 Those who are baptized and by this means incorporated into Christ's Mystical Body, His Church, must attach the greatest importance to this event. They must be acutely aware of being raised to a higher status, of being reborn to a supernatural life, there to experience the happiness of being God's adopted sons, the special dignity of being Christ's brothers, the blessedness, the grace and the joy of the indwelling Holy Spirit. They have indeed been called to a new kind of life, but they have lost nothing of their own humanity except the unhappy state of original sin. Rather, the humanity in them is now capable of bearing the fairest flowers of perfection and the most precious and holiest of fruits. To be a Christian, to have received holy Baptism, must not be looked upon as something of negligible importance. It must be something which thrills the baptized person to the very core of his being. He must look upon it with the eyes of the Christians of the early Church, as an "illumination" which draws down upon his soul the life-giving radiance of divine truth, opens heaven to him, and sheds upon this mortal life that light which enables him to walk as a child of the light toward the vision of God, the wellspring of eternal happiness.
Source: Ecclesiam Suam (Vatican.va)