According to BXVI, the mystery of the Cross “draws us in and gives a new value to our life,” urging us to practise the “incarnate obedience” of Christ. The significance of the term "incarnate obedience" is meant to point us to the need of obeying God by “offering one’s whole existence to God…the whole person becomes ‘Word-like’, ‘God-like.’” Our physical existence - our body - is penetrated by the Word and becomes a gift to God. This, in a word, is the priestly charism of a Christian's baptismal grace: offering up one's body as a living sacrifice pleasing and acceptable to God - a religious practice faithfully followed by the Levitical priests in Old Testament times using animal bodies, which was but a transitory sign pointing to the eternal High Priest Jesus Christ's ultimate sacrifice of his own body on the Cross for all mankind.
(Ref: Jesus of Nazareth II, p. 236.)