Youcat commented through CCC - Question n. 78 - Part I.

YOUCAT Question n. 78 - Part I. Why can we grasp Jesus only as a “mystery”?

(Youcat answer) Jesus extends into God; therefore we cannot understand him if we exclude the invisible divine reality.        

A deepening through CCC

(CCC 525) Jesus was born in a humble stable, into a poor family (Cf. Lk 2:61). Simple shepherds were the first witnesses to this event. In this poverty heaven's glory was made manifest (Cf. Lk 2:8-20). The Church never tires of singing the glory of this night: The Virgin today brings into the world the Eternal and the earth offers a cave to the Inaccessible. The angels and shepherds praise him and the magi advance with the star, For you are born for us, Little Child, God eternal! (Kontakion of Romanos the Melodist).    

Reflecting and meditating 

(Youcat comment) The visible side of Jesus points to the invisible. We see in the life of Jesus numerous realities that are powerfully present but that we can understand only as a mystery. Examples of such mysteries are the divine Sonship, the Incarnation, the Passion, and the Resurrection of Christ.

(CCC Comment)

(CCC 526) To become a child in relation to God is the condition for entering the kingdom (Cf. Mt 18:3-4). For this, we must humble ourselves and become little. Even more: to become "children of God" we must be "born from above" or "born of God" (Jn 3: 7; 1:13; 1:12; cf. Mt 23:12). Only when Christ is formed in us will the mystery of Christmas be fulfilled in us (Cf. Gal 4:19). Christmas is the mystery of this "marvellous exchange": O marvellous exchange! Man's Creator has become man, born of the Virgin. We have been made sharers in the divinity of Christ who humbled himself to share our humanity (LH, Antiphon I of Evening Prayer for January 1st).    

(This question: Why can we grasp Jesus only as a “mystery”? is continued)