When we profess our belief in eternal life, it is a profession of faith in the living God. Because there is a God, we, whom he calls and sees, know that we shall not fall into a vacuum. For that reason, belief in eternal life becomes a very practical testimony. . . Such a testimonial is practical because the whole measure of our lives is determined from this standpoint. This means that we must live for what is lasting. Faith has as its goal. . .that there be an interchange of life, that Christ’s life and ours be intertwined, that our lives be inscribed in his and his in ours, that the promise be fulfilled that St. Teresa of Avila heard addressed to her by the Lord: “Do not be troubled; my concerns are yours and your concerns are mine.” We should live in such a way that this interchange of lives becomes a reality, that his concerns truly do become ours and ours become his, and that Christ’s life and ours become inseparable.
– Pope Benedict XVI