"This evening" Benedict XVI concluded, "you caused us to turn our hearts to Mary in prayer, the most beloved prayer of Christian tradition. Yet you also led us back to the beginning of our journey of faith, to the liturgy of Baptism, the moment in which we became Christian: an invitation always to drink from the only water that can quench our thirst - the living God - and to commit ourselves day after to day to rejecting evil and to renewing our faith with the affirmation 'I believe!'"(Vatican Information System, 1 September 2011) A few brief responses:
1) It is nice to see the pope admitting what a lot of his English-speaking servants deny, namely that his religion prays to Mary. His reference is to the Hail Mary (the Ave Maria).
2) I'm sure that the Hail Mary is the most beloved prayer to those in the Roman communion. However, it ought not to be. The prayer was not taught or practiced by the Lord Jesus or His apostles. It is a tradition of men, not a tradition of God, even though it incorporates portions of God's word.
3) There's a more natural choice for the most beloved prayer - the Kyrie Eleison (Господи Помилуй - "Lord Have Mercy!"). After all, that prayer can succinctly express both repentance of sin and trust in Christ.
4) Alternatively, the model of our prayers, the Lord's Prayer (Pater Noster) would be an excellent choice for the most beloved prayer.
5) One does not become a Christian at Baptism. Christians (and their children) come to baptism. Baptism signifies and seals what faith grasps. Whoever believes is a Christian, and therefore ought to be baptized.
6) I'm not a fan of mixing the metaphors of baptism and the water that is drunk (there's not any intentional drinking of water in Baptism). Nevertheless, the pope is right in pointing to that living water as the uniquely thirst-quenching water. If only he would learn that one who drinks once of this water will never thirst again!
John 4:13-14 Jesus answered and said unto her, Whosoever drinketh of this water shall thirst again: but whosoever drinketh of the water that I shall give him shall never thirst; but the water that I shall give him shall be in him a well of water springing up into everlasting life.
Yet Rome teaches (and the pope has not rejected) that men can again thirst: that they can commit a "mortal sin" and - in essence - lose their salvation. It is great that the pope has appealed to one of Christ's metaphors, but would that God would open the pope's eyes to see the whole truth!