11 Wherefore, to love both countries, that of earth below and that of heaven above, yet in such mode that the love of our heavenly surpass the love of our earthly home, and that human laws be never set above the divine law, is the essential duty of Christians, and the fountainhead, so to say, from which all other duties spring. The Redeemer of mankind of Himself has said: "For this was I born, and for this came I into the world, that I should give testimony to the truth."(9) In like manner: "I am come to cast fire upon earth, and what will I but that it be kindled?"(10) In the knowledge of this truth, which constitutes the highest perfection of the mind; in divine charity which, in like manner, completes the will, all Christian life and liberty abide. This noble patrimony of truth and charity entrusted by Jesus Christ to the Church she defends and maintains ever with untiring endeavor and watchfulness.
Source: Sapientiae Christianae (Vatican.va)