Following and building upon the work of the German priest Romano Guardini, the younger theologian, Joseph Ratzinger published Introduction to Christianity. Here are two quotations to ponder:
Both the poverty of human existence and its fullness point to God. Where men have experienced existence in its fullness, its wealth, its beauty, and its greatness, they have always become aware that this existence is an existence for which they owe thanks.” and “Where man experiences his solitariness, he experiences at the same time how much his whole existence is a cry for the ‘You’ and how ill-adapted he is to be only an ‘I’ in himself.
And
Perhaps in the last analysis it is impossible to escape a paradox whose logic is completely disclosed only to the experience of a life based on faith. Anyone who entrusts himself to a life of faith becomes aware that both exist: the radical character of grace that frees helpless man and,no less, the abiding seriousness of the responsibility that summons man day after day. Both together mean that the Christian enjoys, on the one hand, the liberating, detached tranquility of him who lives on that excess of divine justice known as Jesus Christ. … This is the source of a profound freedom, a knowledge of God’s unrepentant love; he sees through all our errors and remains well disposed to us. … At the same time, the Christian knows, however, that he is not free to do whatever he pleases, that his activity is not a game that God allows him and does not take seriously. He knows that he must answer for his actions, that he owes an account as a steward of what has been entrusted to him. There can only be responsibility where there is someone to be responsible to, someone to put the questions. Faith in the Last Judgment holds this questioning of our life over our heads so that we cannot forget it for a moment. Nothing and no one empowers us to trivialize the tremendous seriousness involved in such knowledge; it shows our life to be a serious business and precisely by doing so gives it its dignity.