In the search for an answer, I would like to begin with the classical form of the dialogue with which the rite of Baptism expressed the reception of an infant into the community of believers and the infant's rebirth in Christ. First of all the priest asked what name the parents had chosen for the child, and then he continued with the question: “What do you ask of the Church?” Answer: “Faith”. “And what does faith give you?” “Eternal life”. According to this dialogue, the parents were seeking access to the faith for their child, communion with believers, because they saw in faith the key to “eternal life”. Today as in the past, this is what being baptized, becoming Christians, is all about: it is not just an act of socialization within the community, not simply a welcome into the Church. The parents expect more for the one to be baptized: they expect that faith, which includes the corporeal nature of the Church and her sacraments, will give life to their child—eternal life. Faith is the substance of hope.This is interesting in the context of the Holy Father's great interest in the older liturgical forms, but also in terms of the theology of baptism which he insists - even for infants - is about more than simply welcoming the believer into the Church. Anyone with a passing familiarity with St Augustine's struggle against Pelagianism will realise that the significance of infant baptism is frequently misrepresented today in a manner which smacks of the old Pelagian heresy. Indeed, Pope Paul VI insisted that the Rite of Baptism for Infants be revised a second time after the Council as the first Rite which was produced seemed to neglect the fact that infant baptism removes the stain of Original Sin. That's not quite the question that the Holy Father is dealing with here - but he is pointing to the supernatural significance of baptism and the fact that the child, although unable to believe himself, does receive the supernatural habitus of faith through baptism.
Pope Benedict follows this with an interesting explanation of death and eternal life, and the curious paradox that for the Christian death is both punishment and remedy.