32. Nations will be reminded by the annual celebration of this feast that not only private individuals but also rulers and princes are bound to give public honor and obedience to Christ. It will call to their minds the thought of the last judgment, wherein Christ, who has been cast out of public life, despised, neglected and ignored, will most severely avenge these insults; for his kingly dignity demands that the State should take account of the commandments of God and of Christian principles, both in making laws and in administering justice, and also in providing for the young a sound moral education.
33. The faithful, moreover, by meditating upon these truths, will gain much strength and courage, enabling them to form their lives after the true Christian ideal. If to Christ our Lord is given all power in heaven and on earth; if all men, purchased by his precious blood, are by a new right subjected to his dominion; if this power embraces all men, it must be clear that not one of our faculties is exempt from his empire. He must reign in our minds, which should assent with perfect submission and firm belief to revealed truths and to the doctrines of Christ. He must reign in our wills, which should obey the laws and precepts of God. He must reign in our hearts, which should spurn natural desires and love God above all things, and cleave to him alone. He must reign in our bodies and in our members, which should serve as instruments for the interior sanctification of our souls, or to use the words of the Apostle Paul, as instruments of justice unto God.
~ Excerpt from QUAS PRIMAS
ENCYCLICAL OF POPE PIUS XI ON THE FEAST OF CHRIST THE KING ~