5 Now, if the natural law enjoins us to love devotedly and to defend the country in which we had birth, and in which we were brought up, so that every good citizen hesitates not to face death for his native land, very much more is it the urgent duty of Christians to be ever quickened by like feelings toward the Church. For the Church is the holy City of the living God, born of God Himself, and by Him built up and established. Upon this earth, indeed, she accomplishes her pilgrimage, but by instructing and guiding men she summons them to eternal happiness. We are bound, then, to love dearly the country whence we have received the means of enjoyment this mortal life affords, but we have a much more urgent obligation to love, with ardent love, the Church to which we owe the life of the soul, a life that will endure forever. For fitting it is to prefer the good of the soul to the well-being of the body, inasmuch as duties toward God are of a far more hallowed character than those toward men.
Source: Sapientiae Christianae (Vatican.va)