In the first nine paragraphs, Pope Benedict has established the Word, Jesus Christ the Son of God, as the root and the meaning ("Logos") of all physical creation, spiritual reality, and salvation history. "Human salvation is the reason underlying everything." (9) This divine foundation puts the dynamic of perfect love at the center of everything; nothing can possibly exist, even sin, apart from a defining relationship with "God who Speaks."
In paragraph 10, he begins working down to the level of the individual:
Those who know God’s word also know fully the significance of each creature... those who build their lives on his word build in a truly sound and lasting way. (10)
This is of course not a novel idea for followers of Christ. The parable of the house built on rock (on The Rock) versus one built on sand will come to mind, for example. In the same way, no created thing is solid and "real" enough to be that foundation stone:
Possessions, pleasure and power show themselves sooner or later to be incapable of fulfilling the deepest yearnings of the human heart. (10)
This brings into this discussion the interior dynamic of continuing conversion and the action of grace; that is, the encounter with and desire for perfect love. As we grow in faith and holiness, we see more and more clearly how things of this world, even when they are good and even as we inevitably use them daily, cannot be the end, the "root and meaning" of our lives. We dig deeper to find and make more central the Rock which is Christ, because only perfect love fulfills perfectly the longing of our hearts. (Cue St. Augustine's famous quote from the Confessions, "Our hearts are restless until they rest in you, O Lord.") This longing brings us face to face with Jesus Christ:
Here the word finds expression not primarily in discourse, concepts or rules. Here we are set before the very person of Jesus. His unique and singular history is the definitive word which God speaks to humanity. We can see, then, why “being Christian is not the result of an ethical choice or a lofty idea, but the encounter with an event, a person, which gives life a new horizon and a definitive direction” (11, citing his own Deus Caritas Est, 1).
The bits and pieces of preparatory revelation, embedded everywhere in creation (as how could they not be?), all point to the definitive revelation of God the Son, Jesus Christ. Only the darkness of sin prevents us from seeing this clearly from the beginning. The fundamental encounter is precisely "illumination:" Christ who is "lumen gentium" literally "in-lumen-ates" us, dispelling the darkness of sin from our spiritual senses. And given a taste of transcendent and perfect love, we long for more:
The constant renewal of this encounter and this awareness fills the hearts of believers with amazement at God’s initiative, which human beings, with our own reason and imagination, could never have dreamt of. (11)