The primary and essential object of catechesis is, to use an expression dear to St. Paul and also to contemporary theology, "the mystery of Christ."
Catechizing is in a way to lead a person to study this mystery in all its dimensions: "to make all men see what is the plan of the mystery...comprehend with all the saints what is the breadth and length and height and depth ...know the love of Christ which surpasses knowledge...(and be filled) with all the fullness of God" (Eph. 3:9, 18-19).
It is therefore to reveal in the Person of Christ the whole of God's eternal design reaching fulfillment in that Person. It is to seek to understand the meaning of Christ's actions and words and of the signs worked by Him, for they simultaneously hide and reveal His mystery. Accordingly, the definitive aim of catechesis is to put people not only in touch but in communion, in intimacy, with Jesus Christ: only He can lead us to the love of the Father in the Spirit and make us share in the life of the Holy Trinity.” (St. John Paul II, Catechesi Tradendae)